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Smart search ranks by meaning as well as keywords (one row per story, last 45 days).
FortiOS and FortiProxy ZTNA Validation Vulnerability Allows Attacker to Perform a Man-in-the-Middle Attack
Fortinet discloses high-severity certificate validation flaw CVE-2026-84393 in FortiOS and FortiProxy Agentless ZTNA portals enabling unauthenticated man-in-the-middle attacks.
Fortinet disclosed CVE-2026-84393 (CVSSv3 7.3, CWE-295) on September 8, 2026 under advisory FG-IR-26-174: improper certificate validation in the Agentless ZTNA portal of FortiOS and FortiProxy. An unauthenticated attacker on the network path could present a forged or mismatched certificate and intercept or tamper with traffic between the portal and backend destinations, with impact classified as information disclosure. Affected versions are FortiOS 7.6.1 through 7.6.6 and FortiProxy 7.6.2 through 7.6.6; the 8.0, 7.4 and 7.2 branches of both products are unaffected. Fortinet urges upgrading to 7.6.7 or later and reports no evidence of exploitation in the wild.
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CISA Warns of Fortinet Heap-based Buffer Overflow Flaw Exploited in Attacks
CISA added actively exploited Fortinet CVE-2025-25249, a critical heap-based buffer overflow in FortiOS, FortiSwitchManager, and FortiSASE, to its KEV catalog.
CVE-2025-25249 is a heap-based buffer overflow (CWE-122/CWE-787) allowing unauthorized code execution by sending specially crafted packets. CISA added it to the Known Exploited Vulnerabilities catalog on September 9, 2026, with a September 12 remediation deadline for federal agencies under BOD 26-04 and mandatory forensic triage of affected environments. Internet-facing Fortinet firewalls and SASE platforms are a likely foothold for credential theft, persistence, and lateral movement; ransomware use is currently listed as unknown.
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Weekly Cybersecurity Newsletter Bulletin – Microsoft 0-day, FortiOS, PAN-OS Flaw, Revolut Data Breach, and 20+ Stories
Weekly roundup: Microsoft patches 973 flaws including two actively exploited zero-days; FortiOS CAPWAP flaw deploys PivotC2 RAT; PAN-OS root RCE disclosed.
Microsoft's September 2026 Patch Tuesday fixed 973 vulnerabilities, including two zero-days under active exploitation: CVE-2026-85880 (Windows ALPC) and CVE-2026-81963 (Windows Update Stack), both elevation-of-privilege bugs. SOCRadar reported active exploitation of CVE-2025-25249 (CVSS 9.8) in FortiOS CAPWAP, deploying a Node.js RAT called PivotC2 that exfiltrates Exchange mailboxes to Wasabi cloud storage; 178 devices were compromised out of 30,000 scanned IPs, attributed to a Russian-speaking financially motivated group. Palo Alto disclosed CVE-2026-0310, a 9.2-rated buffer overflow enabling root code execution on PA-Series firewalls, and Fortinet disclosed CVE-2026-84393, a ZTNA certificate validation MITM flaw. Cyera also revealed CVE-2026-6471 ('PostGREShell'), a 12-year-old PostgreSQL logical-decoding flaw allowing code execution via REPLICATION-privileged accounts.
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UI DoS attack
FortiOS web interface is vulnerable to unauthenticated slow HTTP denial-of-service attacks via crafted requests (CVSS 5.0).
Fortinet advisory FG-IR-26-162 details an unbounded resource allocation flaw (CWE-770) in FortiOS, scored CVSSv3 5.0. An unauthenticated attacker can launch a slow HTTP denial-of-service attack against the FortiOS web interface using crafted HTTP requests. The advisory was revised on 2026-08-12 and does not state that exploitation has been observed.
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Stack buffer overflow in WAD
FortiOS explicit proxy WAD daemon stack buffer overflow (CVSS 5.1) allows code execution only with Kerberos and SOCKS configured.
Fortinet advisory FG-IR-26-161 describes a stack-based buffer overflow (CWE-121) in the WAD daemon of FortiOS explicit proxy, scored CVSSv3 5.1. Exploitation requires an attacker able to bypass stack protection and ASLR, and the explicit proxy must be configured with Kerberos authentication and SOCKS enabled. If successful, it yields arbitrary code or command execution in the WAD daemon context via crafted sockets. No exploitation is reported in the advisory.
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Hackers Exploit FortiGate SSL-VPN Flaw to Breach Thai ISP and Deploy MeshCentral Backdoor
Threat actors exploited FortiOS SSL-VPN flaw CVE-2024-21762 to breach Thai ISP Triple T Broadband, gaining root-level persistence via MeshCentral agents.
Attackers exploited CVE-2024-21762, an out-of-bounds write enabling unauthenticated RCE in FortiOS SSL-VPN, against Triple T Broadband's FortiGate 60F at mail.3bb.co.th, launching a Node.js reverse shell via a ROP payload. Hunt.io uncovered the operation through an exposed staging directory at 92.63.180[.]133:8888 containing 298 files of exploits, credential-harvesting scripts, session cookies, and a device inventory. Post-compromise, the actors deployed MeshCentral agents (device group TH-3BB, C2 www.ayuthayatech.com) running as root, plus a hidden SUID backdoor at /usr/local/bin/.rc, and also targeted an internal Pentaho/Tomcat server with Ghostcat (CVE-2020-1938). A cleanup script removed logs, shell histories, and web shells while deliberately preserving the MeshCentral agent and SUID backdoor.
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Null Pointer Dereference in Log Report
Fortinet patched a low-severity null pointer dereference (CVSS 2.5) in FortiOS, FortiProxy, and FortiPAM that lets authenticated attackers crash the httpsd daemon.
Fortinet advisory FG-IR-26-173 describes a NULL pointer dereference vulnerability (CWE-476) in FortiOS, FortiProxy, and FortiPAM, scored CVSSv3 2.5. An authenticated attacker can crash the httpsd daemon via crafted HTTP requests, causing a denial of service. The advisory was revised on 2026-09-08.
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Fortinet security advisory (AV26-023) - Update 1
CISA added Fortinet CVE-2025-25249, a heap-based buffer overflow in the cw_acd daemon, to its KEV catalog; Canadian Cyber Centre urges patching.
The Canadian Centre for Cyber Security updated advisory AV26-023, which relays January 2026 Fortinet advisories covering FortiFone, FortiOS, FortiSASE, FortiSIEM, and FortiSwitchManager. On September 9, 2026, CISA added CVE-2025-25249, a heap-based buffer overflow in the cw_acd daemon, to its Known Exploited Vulnerabilities catalog. Related Fortinet flaws include unauthenticated local configuration access (CVE-2025-47855) and unauthenticated remote command injection (CVE-2025-64155). Administrators should review the advisories and apply available updates.
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Fortinet security advisory (AV26-898)
Canadian Cyber Centre advisory AV26-898 flags Fortinet vulnerabilities across FortiOS, FortiProxy, FortiPAM, FortiSandbox and FortiMonitorOnSight, urging administrators to apply updates
The Canadian Centre for Cyber Security relayed Fortinet PSIRT advisories (AV26-898) listing vulnerabilities affecting FortiOS 7.6.1-7.6.6, FortiProxy 7.6.2-7.6.6, FortiPAM Chrome extensions 7.4/8.0, FortiSandbox 4.4 and 5.0, FortiSandbox Cloud and PaaS 5.0.4-5.0.5, and FortiMonitorOnSight 7.2. The bulletin does not detail individual CVEs or exploitation. Administrators and users are encouraged to review the linked Fortinet advisories and apply the necessary updates.
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Gunra Ransomware Exploits Fortinet FortiOS, FortiProxy Flaws to Breach Networks
CISA, FBI, and South Korean agencies warn Gunra ransomware, with 51 victims since April 2025, exploits Fortinet flaws for double-extortion attacks on critical infrastructure.
CISA, the FBI, and South Korean agencies warned of Gunra ransomware attacks targeting healthcare, financial services, government, and professional services worldwide. The Conti-derived operation exploits internet-facing Fortinet FortiOS and FortiProxy flaws CVE-2024-55591 and CVE-2025-24472 for initial access, then deploys double extortion with Salsa20/ChaCha20 encryption and publishes non-payers on a leak site within five to seven days. Ransomware.Live lists 51 victims since April 2025, mostly in South Korea, Brazil, Spain, Thailand, and Hong Kong. The group uses Impacket tools for SMB lateral movement and NTDS credential dumping, tampers with VDI authentication to accept a designated OTP value to bypass MFA, and launched a RaaS affiliate program in January 2026 under the new alias Golden Community.
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Hackers Actively Exploiting FortiGate Firewalls to Deploy Custom Node.js Malware
Attackers actively exploit CVE-2025-25249 in FortiGate firewalls to deploy PivotC2, a Node.js RAT that decrypts VPN and admin credentials.
SOCRadar assesses with high confidence that threat actors are actively exploiting CVE-2025-25249, a CVSS 9.8 heap buffer overflow in the cw_acd daemon (CAPWAP, UDP 5246) affecting FortiOS 6.4-7.6.3 and FortiSwitchManager 7.0.x/7.2.x. Attackers deploy fortirun.bin and PivotC2, a Node.js post-exploitation framework that harvests configurations and decrypts SSL-VPN, wireless, and admin credentials using AES-256-CBC and AES-128-GCM. Over 30,000 FortiGate IPs were scanned and 178 devices compromised, including two confirmed full intrusions of US organizations with Exchange mailbox exfiltration to Wasabi storage. STRU attributes the campaign to a Russian-speaking, financially motivated cybercrime operator.
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Hackers Exploit Critical FortiGate Flaw to Deploy AI-Assisted PivotC2 RAT
SOCRadar says attackers exploit FortiGate CVE-2025-25249 to deploy the PivotC2 Node.js RAT, compromising 178 of 30,000 targeted devices and stealing credentials.
SOCRadar's Threat Research Unit reports active exploitation of CVE-2025-25249, a CVSS 9.8 heap-based buffer overflow in the cw_acd daemon of FortiOS and FortiSwitchManager, via crafted CAPWAP requests to UDP port 5246, compromising at least 178 of 30,000 targeted internet-exposed FortiGate devices since July 2026. The campaign deploys PivotC2, a Node.js RAT that provides interactive shells, SOCKS5/HTTP proxying, port forwarding, network scanning, and automated configuration harvesting that decrypts stored FortiGate credentials, including VPN pre-shared keys, SSL-VPN credentials, and LDAP secrets. Russian-language artifacts, AD enumeration, browser credential theft, RDP enablement, and exfiltration of Exchange .pst files to Wasabi S3 point to a Russian-speaking, financially motivated group; two US organizations confirmed full-network intrusions. Fixes include FortiOS 7.6.4/7.4.9/7.2.12/7.0.18+ and FortiSwitchManager 7.2.7/7.0.6+, plus blocking CAPWAP on internet-facing interfaces.
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ZTNA Portal Improper Certificate Validation
Fortinet fixed an improper certificate validation flaw (CVSS 7.3) in FortiOS and FortiProxy Agentless ZTNA portal enabling unauthenticated man-in-the-middle attacks on backend traffic.
Fortinet advisory FG-IR-26-174 discloses an improper certificate validation vulnerability (CWE-295) in the FortiOS and FortiProxy Agentless ZTNA portal, rated CVSSv3 7.3. A remote and unauthenticated attacker can perform a man-in-the-middle attack on the communication channel between the ZTNA portal and the backend destination website. The advisory was revised on 2026-09-08.
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Fortinet Patches Critical Vulnerabilities in FortiMonitorOnSight, Chrome Extension
Fortinet patched 10 vulnerabilities including two critical authentication flaws, CVE-2026-84390 (CVSS 9.6) and CVE-2026-84388 (CVSS 9.1), in FortiMonitorOnSight and the FortiPAM Chrome extension.
Fortinet's September patch release fixes CVE-2026-84390, a sensitive-information issue in the FortiMonitorOnSight web portal that lets unauthenticated attackers bypass authentication with forged or reused JWTs. CVE-2026-84388 is an improper authentication flaw in the Fortinet Privileged Access Agent Chrome extension that can allow attackers to proxy a user's browser traffic via a malicious website, requiring upgrades to both FortiPAM 1.9.1/1.8.4 and extension 8.0.1.123+. High-severity information disclosure in FortiSandbox (CVE-2026-26084) and man-in-the-middle risk in the FortiOS/FortiProxy Agentless ZTNA portal (CVE-2026-84393) were also fixed, alongside medium/low issues across FortiManager, FortiAnalyzer, FortiSOAR, FortiClient, FortiSIEM and others. Fortinet did not indicate any of the flaws are being exploited in the wild.
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Fortra security advisory (AV26-906)
Canada's Cyber Centre advises that Fortra GoAnywhere MFT Endpoint versions prior to 7.10.2 are affected by a path traversal vulnerability.
The Canadian Centre for Cyber Security issued advisory AV26-906 noting that Fortra GoAnywhere MFT Endpoint versions prior to 7.10.2 are affected by a path traversal vulnerability. The advisory was published September 10, 2026, referencing Fortra's own security advisory. No exploitation details or CVE id are provided; administrators are urged to review the links and apply the 7.10.2 update.
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August 2026 CVE Landscape
Insikt Group catalogs 73 high-impact August 2026 CVEs (43 Very Critical), including PaperCut, Zimbra, and Metabase flaws actively exploited or weaponized.
Recorded Future's Insikt Group identified 73 high-impact vulnerabilities in August 2026, 43 rated Very Critical, spanning 45 vendors with Microsoft accounting for roughly 11%. 31 vulnerabilities surfaced via CISA's KEV catalog, with others validated via open sources, vendor telemetry, and honeypot data. New Nuclei detection templates were released for CVE-2025-62593 (Ray), CVE-2026-72898 (Metabase), and CVE-2026-9198 (IBM Langflow). The report also highlights two AI-assisted operations: UAT-10147 exploited Zimbra, AjaxPro, Nacos, and Telerik servers before using DeepAudit and PentestGPT post-compromise, while a separate Chinese-speaking actor weaponized Hermes Agent and DeepSeek in a failed attempt.
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Arbitrary process termination from exposed minifilter communication port
Fortinet FortiClient Windows fortimon3 driver flaw (CVSS 4.7) lets authenticated attackers terminate arbitrary processes via exposed minifilter communication port.
Fortinet advisory FG-IR-26-165 discloses an unverified ownership vulnerability (CWE-283, CVSSv3 4.7) in the FortiClient Windows fortimon3 minifilter driver. An authenticated attacker can terminate arbitrary processes through an exposed minifilter communication port. The advisory was revised on 2026-09-08.
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Heap overflow in kernel driver due to missing size validation
Fortinet fixes a CVSS 7.3 heap overflow in the FortiClient Windows kernel driver enabling code execution via crafted DNS responses.
Fortinet PSIRT advisory FG-IR-26-156, revised 2026-08-12, describes a heap-based buffer overflow (CWE-120, buffer copy without checking input size) in the FortiClient Windows kernel driver, scored CVSSv3 7.3. An unauthenticated attacker positioned to alter or craft DNS responses for a targeted host could execute arbitrary code via malicious packets. No CVE identifier or exploitation status is provided in the advisory text, so administrators should check the full bulletin for affected versions and fixed releases.
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Risky Bulletin: Russia starts blocking DoH and DoT
Russian users report blocks on DoH and DoT servers, including Cloudflare 1.1.1.1 and Google 8.8.8.8, in an apparent censorship crackdown.
Russian internet users began reporting failures connecting to DNS-over-HTTPS and DNS-over-TLS servers, suggesting a government crackdown on the two privacy protocols. The blocks reportedly cover Cloudflare's 1.1.1.1 and Google's 8.8.8.8 resolvers; Roskomnadzor has not officially confirmed the action. The agency tested a similar block in March on Beeline's network and had named DoH for blocking as early as 2021. The bulletin also briefly notes state-sponsored phishing of EU officials, a DDoS against Norway's Digdir, the ReliaQuest/ShinyHunters dispute, and older ransomware and breach disclosures.
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FortiSandbox Vulnerability Allows Attackers to Access Sensitive Information via Crafted HTTP Requests
Fortinet disclosed CVE-2026-26084 (CVSS 8.9), an unauthenticated information-disclosure flaw in the FortiSandbox web UI, urging upgrades.
Fortinet patched CVE-2026-26084, a CWE-284 improper access control flaw in the shared web UI of FortiSandbox, FortiSandbox Cloud, and FortiSandbox PaaS that lets unauthenticated attackers read sensitive data via crafted HTTP requests. Affected releases include FortiSandbox 5.0.0-5.0.5 and 4.4.0-4.4.8, Cloud 5.0.4-5.0.5, and PaaS 5.0.4-5.0.5; fixes arrive in 5.0.6+ and 4.4.9+, while FortiSandbox 5.2 and Cloud 4.4 are unaffected. The issue was found internally by Fortinet's Product Security team, and the company reports no evidence of exploitation in the wild. Disclosure carries only confidentiality impact, but exposed sandbox configurations and logs could aid follow-on attacks.
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September 2026 Patch Tuesday roundup: Plugs for two zero day holes among almost 1,000 fixes in Windows
Microsoft's September 2026 Patch Tuesday ships 964 fixes including two exploited Windows zero-days (CVE-2026-85880, CVE-2026-81963) and a wormable DNS RCE.
Microsoft's September 2026 Patch Tuesday includes 964 Microsoft vulnerabilities requiring customer action, a record attributed to AI-assisted bug discovery, plus 174 third-party/open-source and 23 Chromium/Edge CVEs. Two zero-days are exploited in the wild: CVE-2026-85880, a Windows ALPC heap overflow enabling AppContainer sandbox escape and privilege escalation, and CVE-2026-81963, a Windows Update Stack escalation to SYSTEM. CVE-2026-69730, an unauthenticated Windows DNS RCE, is not yet exploited but Microsoft expects exploitation, and roughly 20 bugs could be wormable. Separately, SAP issued a critical CVSS 10.0 fix for the EPP component used in S/4HANA and NetWeaver.
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Server-Side Request Forgery (SSRF)
Fortinet discloses a low-severity SSRF in the FortiSIEM GUI allowing authenticated attackers to send requests from targeted devices.
Fortinet PSIRT advisory FG-IR-26-159, revised 2026-08-12, describes a server-side request forgery (CWE-918) in the FortiSIEM GUI, scored CVSSv3 3.4. An authenticated attacker can send HTTP requests originating from the targeted device via specially crafted requests, potentially enabling internal network probing. No CVE identifier or exploitation status is included in the advisory text.
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H1 2026 Malware Vulnerability Trends
Recorded Future's H1 2026 report finds 215 actively exploited CVEs, RAT dominance, NFC payment fraud, and AI-augmented but not autonomous tradecraft.
Recorded Future's Insikt Group identified 215 actively exploited CVEs in H1 2026, up 34% from 161 in H1 2025, with the most impactful flaws combining network reachability, no authentication, and code execution. AsyncRAT was the top malware family, with AsyncRAT, Cobalt Strike, XWorm, Stealc, and REMCOS remaining top-ten staples; Android NFC malware like NFCShare and NGate enabled payment card theft and ATM cash-outs. AI-enabled attacks remained additive to established tradecraft, concentrated in Levels 1-3 of Recorded Future's AIM3 maturity model, with AI-assisted vulnerability research (e.g., Claude Mythos fixing 271 Firefox bugs in Firefox 150) inflating NVD disclosure volumes 43% above the prior six-month average. The report urges defenders to prioritize remotely exploitable RCE flaws, behavioral detection, developer credential security, and third-party oversight.
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New Phishing Campaign Abuses Windows Mshta.exe to Steal Credentials and Secrets
Fortra researchers track an active phishing campaign targeting Spanish speakers that abuses mshta.exe to run HTA payloads for reconnaissance and credential theft.
Fortra's FIRE team says a phishing campaign active since June 2026 targets Spanish-speaking users with invoice ('Facturación') and judicial ('Aviso Judicial') lures, many sent via libero.it/italiaonline.it infrastructure with SCL:-1 markings to bypass anti-spam. Clicking embedded links delivers an HTA launcher executed via mshta.exe, which hides its window off-screen, builds dynamic C2 URLs, and performs reconnaissance using WMI, PowerShell, and environment-variable inspection. A second-stage JavaScript dropper uses HTML smuggling to reconstruct a Base64-encoded ZIP in the browser, delivering a 7-Zip self-extracting executable disguised as a Firefox installer; staged design allows later delivery of credential stealers or ransomware. Defenders are urged to block archivogratuito[.]online and shortener domains goo[.]su, abrir[.]link, and abre[.]ai, and to restrict mshta.exe execution via AppLocker or ASR rules.
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July 2026 CVE Landscape
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Fortinet FortiSandbox Vulnerability Allows Unauthenticated Attackers to Access Sensitive Information
Fortinet fixed CVE-2026-26084, an unauthenticated access-control flaw in FortiSandbox GUI rated 8.9 CVSS, with no known exploitation yet.
Fortinet disclosed CVE-2026-26084 (advisory FG-IR-26-166), a CWE-284 improper access control flaw in the GUI of FortiSandbox, FortiSandbox Cloud and FortiSandbox PaaS, rated 8.9 CVSS v3.1. An unauthenticated remote attacker can send specially crafted HTTP requests to control NAT rules and expose sensitive information. Affected versions include FortiSandbox 4.4.0-4.4.8 and 5.0.0-5.0.5 (plus Cloud/PaaS 5.0.4-5.0.5), fixed in 4.4.9 and 5.0.6. Fortinet researcher Adham El Karn found the flaw internally and the September 8 advisory reports no known exploitation.
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Hackers Deploy Casbaneiro Banking Trojan That Activates When Victims Open Bank Websites
Fortinet details Casbaneiro banking Trojan campaign hitting Latin American bank customers via invoice-themed PDF phishing, with AutoIt loading, RegSvcs.exe injection, and bank-site-triggered activation.
Fortinet identified an August 2026 Casbaneiro banking Trojan campaign targeting users in Argentina, Peru, Colombia, and Mexico through phishing PDFs styled as urgent invoices or legal notices. The staged chain uses IP-based geo-filtering, a Base64-encoded ZIP, an HTA file, and a legitimate AutoIt interpreter before injecting into RegSvcs.exe or mobsync.exe and persisting via a Startup shortcut. The Trojan exfiltrates address book and Outlook data unencrypted, stays dormant until victims visit targeted bank sites, then accepts commands for keyboard control, clipboard pasting, file execution, and command execution. It uses an expected HTTP 403 response from a second server and malformed HTTP requests to complicate network analysis.
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Unauthenticated Control of NAT Rules Leading to Exposure of Sensitive Information
Fortinet fixed an improper access control flaw (CVSS 8.9) in FortiSandbox, FortiSandbox Cloud, and FortiSandbox PaaS letting unauthenticated attackers access sensitive information.
Fortinet advisory FG-IR-26-166 discloses an improper access control vulnerability (CWE-284) in the FortiSandbox, FortiSandbox Cloud, and FortiSandbox PaaS web UI, rated CVSSv3 8.9. The advisory title indicates unauthenticated control of NAT rules leading to exposure of sensitive information. An unauthenticated attacker can access sensitive data via crafted HTTP requests. The advisory was revised on 2026-09-08.
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Fortinet Vulnerability Ransomware
Ransomware operators are exploiting a Fortinet vulnerability, per the Infosecurity Magazine headline; article details unavailable.
Infosecurity Magazine's headline indicates ransomware activity tied to a Fortinet vulnerability. The article body was not available, so the specific CVE, affected versions and victim details are unconfirmed.
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The 12 Best Managed Firewall Services, Compared and Priced
GBHackers compares 12 managed firewall service providers, naming Fortinet best value and Secureworks best detection while flagging recent ownership changes.
The buyer's guide evaluates 12 managed firewall/MSSP providers across cost tiers, contract terms, and service models. Fortinet is rated best value, Secureworks best detection, NTT Data best global reach, and Cato Networks best for organizations wanting to stop owning firewalls. The article highlights that Secureworks was acquired by Sophos for roughly $859 million in February 2025, the Trustwave-Cybereason merger was terminated in March 2025, LevelBlue is the rebranded AT&T Cybersecurity business, and Comcast Business absorbed Masergy.
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