CISA added actively exploited Cisco FMC, Chrome V8, Fortinet and Citrix NetScaler flaws to its KEV catalog, ordering federal patching by September 12.
CISA added four actively exploited vulnerabilities to its Known Exploited Vulnerabilities catalog. CVE-2026-20079 (CVSS 10.0) is an unauthenticated authentication bypass in Cisco Secure Firewall Management Center's web interface enabling script execution and potential root access. CVE-2026-87491 (CVSS 8.8) is an out-of-bounds write in Chrome's V8 engine — the seventh actively exploited Chrome zero-day of 2026 — fixed in Chrome 153.0.8010.36. CVE-2025-25249 (CVSS 8.1) is a heap-based buffer overflow in FortiOS/FortiSwitchManager's cw_acd daemon being exploited with the PivotC2 RAT, and CVE-2026-19490 (CVSS 9.3) is a NetScaler SAML HTTP-Redirect authentication bypass; federal agencies must patch by September 12, 2026.
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.
CISA adds actively exploited Cisco, Citrix, and Fortinet edge-device flaws to KEV catalog, ordering federal agencies to patch by September 12, 2026.
CISA added CVE-2026-20079 (Cisco Secure Firewall Management Center authentication bypass, CVSS 10.0), CVE-2026-19490 (Citrix NetScaler ADC/Gateway authentication bypass, CVSS 9.3), and CVE-2025-25249 (FortiOS heap buffer overflow, CVSS 7.3) to the Known Exploited Vulnerabilities catalog with a September 12, 2026 deadline for FCEB agencies. Cisco confirmed active exploitation of CVE-2026-20079 in August 2026, while Previdian honeypots logged 56 NetScaler exploitation attempts since September 3. SOCRadar attributes Fortinet exploitation to a financially motivated Russian-speaking actor deploying the PivotC2 Node.js RAT, infecting 178 of over 3,000 targeted IP addresses, mostly in the US.
Threat actors exploit Fortinet heap-based buffer overflow CVE-2025-25249 to deploy PivotC2 RAT, infecting 178 devices and exfiltrating data from US targets.
SOCRadar reports exploitation of an unauthenticated remote code execution vulnerability, CVE-2025-25249 (CVSS 7.4), patched in January in FortiOS and FortiSwitchManager. Attackers scanned over 30,000 IP addresses, infected 178 devices with PivotC2 RAT, and at least two intrusions resulted in data exfiltration, primarily targeting US entities. SOCRadar attributes attacks to a likely Russian-speaking cybercrime actor and suggests the RAT was AI-assisted, in use since July 2026. CISA added the CVE to the KEV catalog with a three-day BOD 26-04 patch deadline for federal agencies.
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.
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.
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.
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.
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.
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.
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.
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.
Heap-Based Buffer Overflow in Fortinet FortiOS, FortiSwitchManager, and FortiSASE
CVE-2025-25249 is a heap-based buffer overflow (CWE-122/CWE-787) in Fortinet FortiOS, FortiSwitchManager, and FortiSASE that allows an attacker to execute unauthorized code or commands. It is triggered by sending specially crafted packets to an affected device, causing an out-of-bounds write in heap memory that can be leveraged for code execution. Successful exploitation gives attackers command execution on the appliance; in observed intrusions against FortiGate firewalls, attackers have deployed custom Node.js malware and a post-exploitation RAT dubbed PivotC2. Any organization running the affected Fortinet products is at risk, with internet-facing FortiGate firewalls the primary concern. The flaw was added to CISA's KEV on 2026-09-09, confirming active exploitation in the wild (ransomware use unknown); no public PoC is known.
· Fortinet FortiOS · Fortinet FortiSwitchManager KEV PoC mass
Authentication bypass to root access in Cisco Secure Firewall Management Center
CVE-2026-20079 is an authentication bypass (CWE-288) in the web interface of Cisco Secure Firewall Management Center (FMC) Software, caused by an improper system process created at boot time. An unauthenticated, remote attacker can exploit it by sending crafted HTTP requests to the FMC web interface, which allows the execution of script files and commands on the device. A successful exploit grants the attacker root access to the underlying operating system, giving full control of the management platform (CVSS 3.1: 10.0, network-exploitable, no privileges or user interaction required, scope changed). The flaw affects Cisco Secure Firewall Management Center (FMC) and Security Cloud Control (SCC) Firewall Management deployments. Cisco has confirmed the vulnerability is being exploited in active attacks, it carries a 35.9% EPSS score (98th percentile), and CISA added it to the Known Exploited Vulnerabilities catalog on 2026-09-09.
Remote Authentication Bypass in Citrix NetScaler ADC and NetScaler Gateway
Citrix NetScaler ADC and NetScaler Gateway contain an authentication-bypass vulnerability (CWE-288, 'using an alternate path or channel') that an unauthenticated remote threat actor can exploit. The flaw is triggerable when the appliance is configured as an AAA virtual server or as a Gateway, including SSL VPN, ICA Proxy, CVPN, or RDP Proxy deployments, allowing the attacker to bypass authentication without valid credentials. A successful bypass could give an attacker access to VPN-protected or AAA-gated resources as an authenticated user; no CVSS score has been published yet. Organizations running affected NetScaler appliances in these configurations are exposed, and affected version ranges are not specified in the available data, so defenders should consult Citrix advisory AL26-019. The flaw was added to CISA's KEV on 2026-09-09, indicating exploitation in the wild; ransomware use is unknown, no public PoC is known, and EPSS assigns a 3.4% probability of exploitation within 30 days (88th percentile).
· Citrix NetScaler ADC and NetScaler Gateway KEV PoC large
Unauthenticated Super-Admin Bypass in Fortinet FortiOS and FortiProxy
CVE-2024-55591 is an authentication bypass (CWE-288) in the Node.js websocket module of Fortinet FortiOS and FortiProxy that lets a remote, unauthenticated attacker gain super-admin privileges via crafted websocket requests. It affects FortiOS 7.0.0 through 7.0.16 and FortiProxy 7.0.0 through 7.0.19 and 7.2.0 through 7.2.12, and is trivially triggerable from the network with no user interaction given network access to the management/websocket interface. Successful exploitation gives full super-admin control of the appliance, which attackers can use to pivot, create persistent access, and deploy ransomware. Any organization running the affected FortiOS or FortiProxy versions, especially with admin interfaces reachable from the internet, is affected. Exploitation is confirmed in the wild: CISA added it to the Known Exploited Vulnerabilities catalog on 2025-01-14, and multiple ransomware crews (reported as Gunra, SuperBlack, and Mora_001) are actively exploiting it.
· Fortinet FortiOS 7.0.0 through 7.0.16 · Fortinet FortiProxy 7.0.0 through 7.0.19 and 7.2.0 through 7.2.12 KEV ransomwarelarge
Actively Exploited Out-of-Bounds Write in Google Chrome V8
CVE-2026-87491 is an out-of-bounds write (CWE-787) in the V8 JavaScript engine in Google Chrome, fixed in Chrome 153.0.8010.36, which Google shipped alongside roughly 230 other security fixes. An attacker can trigger the flaw remotely by luring a user (user interaction required) into opening a crafted HTML page that corrupts memory in V8. Successful exploitation allows the attacker to execute arbitrary code inside the Chrome browser sandbox, which constrains but does not eliminate the impact. All Google Chrome users running versions prior to 153.0.8010.36 are affected; because the flaw resides in V8, CISA tracks it as 'Google Chromium V8', and other Chromium-based browsers may inherit the fix in their own updates. The flaw is being actively exploited in the wild — it is the seventh actively exploited Chrome zero-day of 2026 and was added to CISA's KEV catalog on 2026-09-09 — though no public proof-of-concept is known and ransomware use is unknown.
· Google Chrome (V8 JavaScript engine; tracked by CISA as 'Google Chromium V8') prior to 153.0.8010.36 KEVmass
Authentication Bypass in Fortinet FortiOS and FortiProxy Grants Super-Admin Access
CVE-2025-24472 is an authentication bypass (CWE-288) in the Fortinet Security Fabric of FortiOS and FortiProxy. A remote, unauthenticated attacker who already knows the serial numbers of both the upstream and downstream devices can send crafted CSF proxy requests to gain super-admin privileges on the downstream device; the attack only works where the Security Fabric is enabled, and the need for serial-number knowledge raises attack complexity. An attacker gains full super-admin control of the downstream Fortinet device, which can serve as a foothold for network-wide compromise. Organizations running affected FortiOS 7.0.x or FortiProxy 7.0.x/7.2.x builds with Security Fabric enabled are in scope. The flaw was added to CISA's KEV catalog on 2025-03-18 with known ransomware use, and multiple ransomware groups (including Gunra, SuperBlack, Mora_001 and Qilin operators) have been reported exploiting Fortinet firewall flaws in recent campaigns.
· Fortinet FortiOS 7.0.0 through 7.0.16 · Fortinet FortiProxy 7.0.0 through 7.0.19 KEV ransomwaremass
Improper Access Control in Fortinet FortiSandbox Exposes Sensitive Data
CVE-2026-26084 is an improper access control flaw (CWE-284) in the web interface of Fortinet's FortiSandbox threat-analysis product line, affecting on-premises 4.4.x and 5.0.x releases as well as the FortiSandbox Cloud and PaaS offerings. An unauthenticated attacker can trigger it remotely by sending crafted HTTP requests to the affected FortiSandbox web service, bypassing access controls without needing credentials or user interaction. A successful attacker gains access to sensitive information handled by the appliance; Fortinet's critical 9.9 CVSS score also reflects a scope change with a high availability-impact component, so defenders should treat the practical impact as potentially broader than simple information disclosure. Any organization running affected versions of FortiSandbox, FortiSandbox Cloud, or FortiSandbox PaaS is in scope, though the product's enterprise appliance/cloud deployment model means the affected population is far smaller than endpoint or firewall software. There is no evidence of exploitation so far: the flaw is not in CISA KEV, has no known public proof-of-concept, and EPSS assigns roughly a 0.2% probability of exploitation within 30 days.
· Fortinet FortiSandbox 5.0.0 through 5.0.5 · Fortinet FortiSandbox 4.4.0 through 4.4.8moderate
Unauthenticated RCE via OS Command Injection in Fortinet FortiSIEM
Fortinet FortiSIEM contains an unauthenticated OS command injection flaw (CWE-78) caused by improper neutralization of special elements used in an OS command. A remote attacker can trigger it by sending crafted TCP requests to the vulnerable service, requiring no credentials or user interaction. Successful exploitation allows execution of unauthorized code or commands on the SIEM host, giving an attacker control over a high-value security monitoring platform. Every current FortiSIEM release branch is affected: 7.4.0, 7.3.0 through 7.3.4, 7.1.0 through 7.1.8, 7.0.0 through 7.0.4, and 6.7.0 through 6.7.10. A public proof-of-concept exploit has been released, and EPSS assigns a 43.2% probability of exploitation within 30 days (99th percentile), though the flaw is not yet in CISA KEV and no confirmed in-the-wild exploitation has been reported.
Sensitive Information in Source Code in Fortinet FortiMonitorOnSight (CVSS 9.8)
CVE-2026-84390 is a critical (CVSS 3.1: 9.8) information-disclosure flaw in Fortinet FortiMonitorOnSight in which sensitive information is included in the product's source code (CWE-540). An unauthenticated, network-located attacker who obtains that embedded material (e.g., secrets or credentials shipped with the code) can use it to gain improper access by subverting access controls; the CVSS vector requires no privileges or user interaction and rates the impact high on confidentiality, integrity, and availability. All FortiMonitorOnSight deployments running the affected 7.2.x releases listed by Fortinet (7.2.0 through 7.2.2 and 7.2.4 through 7.2.7) are affected. Fortinet has shipped fixes for this flaw, but there is no public proof-of-concept, the vulnerability is not in CISA KEV, and no exploitation in the wild is currently known.
· Fortinet FortiMonitorOnSight 7.2.0 through 7.2.2 · Fortinet FortiMonitorOnSight 7.2.4 through 7.2.7niche
Certificate Host-Mismatch Validation Flaw in FortiOS and FortiProxy ZTNA
CVE-2026-84393 is an improper certificate validation flaw (CWE-297, host mismatch) in the ZTNA (Zero Trust Network Access) functionality of Fortinet FortiOS and FortiProxy, in which certificates are not correctly verified against the intended host. Per the related advisory headline, a network-adjacent or on-path attacker can exploit it to perform a man-in-the-middle attack against ZTNA connections, and the vendor describes the impact as information disclosure; the CVSS vector additionally rates confidentiality, integrity, and availability impact as high. Organizations running affected FortiOS 7.6.1 through 7.6.6 or FortiProxy 7.6.2 through 7.6.6 with ZTNA enabled are exposed. As of now there is no known exploitation, no public proof-of-concept, the flaw is not in CISA's KEV catalog, and EPSS puts 30-day exploitation probability at just 0.2% (5th percentile), so risk is currently low but patching is still warranted given the high CVSS score.
· Fortinet FortiOS 7.6.1 through 7.6.6 · Fortinet FortiProxy 7.6.2 through 7.6.6large
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