Ongoing exploitation of Cisco Catalyst SD
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CVE-2026-34486: Apache Tomcat EncryptInterceptor Fail-Open Bypass
Technical analysis shows CVE-2026-34486 is a one-line fail-open regression in Tomcat Tribes enabling unauthenticated RCE via Java deserialization.
CVE-2026-34486 is a fail-open regression in Tomcat's Tribes EncryptInterceptor, introduced while fixing the CVE-2026-29146 padding-oracle flaw; Apache rated it Important and NVD scores it 7.5 High. Decryption failures are now forwarded to an unfiltered ObjectInputStream, and public PoC repositories demonstrate unauthenticated RCE on default port 4000 when clustering, the EncryptInterceptor, a reachable receiver and deserialization gadgets are all present. Affected releases 9.0.116, 10.1.53 and 11.0.20 are fixed in 9.0.117, 10.1.54 and 11.0.21; Tomcat 8.5 is unaffected.
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Active exploitation of Cisco Secure Firewall Management Center vulnerabilities
Cisco Talos reports in-the-wild exploitation of critical FMC flaw CVE-2026-20079 by three clusters including a Sandworm-linked APT and Qilin ransomware affiliates.
Cisco Talos is tracking active exploitation of CVE-2026-20079 (CVSS 10.0), an authentication bypass in Cisco Secure Firewall Management Center that lets unauthenticated remote attackers execute scripts and obtain root access, and CVE-2026-20316 (CVSS 5.3), which permits low-privileged logins and can be chained for privilege escalation. Talos identified three post-compromise clusters: UAT-12197 deploying JSP web shells and a JAR command executor for credential theft; UAT-11823, an APT overlapping with Sandworm, deploying a Netcat reverse shell and Cyclops Blink malware; and UAT-11988, assessed as a ransomware operator with TTPs consistent with Qilin affiliates. Hotfixes are available, with a comprehensive hardening release due the week of September 14, 2026.
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Cisco FMC flaws exploited by ransomware gang, state-sponsored hackers
Cisco Talos confirms ransomware and state-sponsored groups exploited CVE-2026-20079 and CVE-2026-20316 in Secure Firewall Management Center, deploying Qilin ransomware and Cyclops Blink.
Cisco Talos identified three threat clusters (UAT-12197, UAT-11823, UAT-11988) exploiting CVE-2026-20079, a CVSS 10.0 authentication bypass, and CVE-2026-20316, a CVSS 5.3 static-credential flaw, in Cisco Secure Firewall Management Center. Qilin affiliates used static credentials for reconnaissance and deployed Qilin ransomware; a Sandworm-linked cluster deployed a Cyclops Blink backdoor via a malicious license.tmp file; a third cluster stole credentials through a JSP web shell. Cisco has released hotfixes and urges immediate installation, with broader patches expected next week.
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Attackers Exploit Critical Cisco FMC Flaw to deploy Qilin ransomware
Three threat groups, including Qilin ransomware operators, exploit critical Cisco FMC flaws CVE-2026-20079 and CVE-2026-20316 for root access, credential theft, and ransomware.
Cisco Talos identified three post-compromise clusters exploiting recently patched Cisco Secure Firewall Management Center flaws. UAT-12197 deploys JSP web shells and harvests credentials; UAT-11823 (with Sandworm-overlapping tooling) installs Cyclops Blink for persistence; UAT-11988 (Qilin) uses static credentials, extensive reconnaissance, SOCKS5 proxies, reverse-SSH tunnels, AV killers, and ransomware deployment. CISA added CVE-2026-20079 to the KEV catalog with a September 12, 2026 patch deadline for federal agencies; Cisco urges immediate hotfix application.
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Critical Cisco FMC Flaws Actively Exploited to Gain Root Access and Deploy Malware
Threat actors actively exploit Cisco FMC CVE-2026-20079 (CVSS 10.0) for root access, with clusters linked to Sandworm and Qilin ransomware.
Cisco Talos warns of active exploitation of CVE-2026-20079, a CVSS 10.0 authentication bypass in Cisco Secure Firewall Management Center allowing unauthenticated root-level code execution, and CVE-2026-20316 (CVSS 5.3), which permits login via a low-privileged static account for privilege escalation. Hotfixes are available now, with a broader hardening release planned for the week of September 14. Three post-compromise activity clusters were identified: UAT-12197 deployed a home.jsp web shell and cmd.jar command executor; UAT-11823, attributed with high confidence to a Sandworm-linked APT, deployed a Netcat reverse shell and Cyclops Blink; and UAT-11988 showed Qilin ransomware tactics including Active Directory enumeration and credential theft before deploying Qilin ransomware.
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Hackers Exploit Critical Cisco Firewall Flaw to Gain Root Access and Deploy Malware
State-sponsored and ransomware actors actively exploit critical Cisco FMC flaws CVE-2026-20079 (CVSS 10.0) and CVE-2026-20316 to gain root access and deploy ransomware.
Cisco Talos confirmed in-the-wild exploitation of CVE-2026-20079 (CVSS 10.0, unauthenticated authentication bypass enabling root command execution) and CVE-2026-20316 (CVSS 5.3, hard-coded static credentials) in Cisco Secure Firewall Management Center. Three activity clusters were identified: UAT-12197 dropping a JSP web shell and credential harvester; UAT-11823, assessed as Sandworm, deploying a Cyclops Blink variant; and UAT-11988, a Qilin ransomware affiliate chaining the flaws before deploying ransomware. CISA added both CVEs to the KEV catalog with a September 12 remediation deadline for federal agencies.
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Cisco FMC Flaws Exploited to Steal Credentials and Deploy Qilin Ransomware
Three threat clusters including a Sandworm-linked group and Qilin ransomware operators exploit Cisco FMC flaws CVE-2026-20079 and CVE-2026-20316.
Cisco Talos identified three clusters of post-compromise activity exploiting CVE-2026-20079 (CVSS 10.0, unauthenticated web-interface authentication bypass enabling root code execution) and CVE-2026-20316 (CVSS 5.3, low-privilege login exposing sensitive data) in Secure Firewall Management Center. UAT-12197 deployed JSP web shells and a JAR-based command executor to query internal databases for credentials; UAT-11823 used a Netcat reverse shell, configuration-harvesting scripts and a Cyclops Blink variant previously attributed to Russia's Sandworm; UAT-11988 used living-off-the-land FMC tooling for reconnaissance before deploying Qilin ransomware. CISA added CVE-2026-20079 to its KEV catalog, requiring FCEB agencies to patch by September 12, 2026; CVE-2026-20316 was added in late July 2026.
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Cisco FMC bugs exploited by nation-state and ransomware actors (CVE-2026-20079, CVE-2026-20316)
Cisco Talos confirms nation-state (Sandworm) and ransomware (Qilin) actors actively exploit CVE-2026-20079 and CVE-2026-20316 in Secure Firewall Management Center.
CVE-2026-20079 is a critical unauthenticated authentication bypass in the FMC web interface allowing root-level script and command execution via crafted HTTP requests; CVE-2026-20316 stems from static hard-coded credentials enabling unauthenticated logins. Cisco Talos detailed three intrusion clusters: web shell and JAR deployment for credential theft, a Sandworm-attributed reverse shell and credential-harvesting implant, and a suspected Qilin ransomware operator chain. Cisco urges immediate hotfixes ahead of a comprehensive hardening release the week of September 16, or taking the FMC management interface offline.
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Organizations Warned of Cisco Secure FMC Exploitation
Cisco and CISA warn that critical FMC authentication bypass CVE-2026-20079 is actively exploited; CISA added it to the KEV catalog with a September 12 deadline.
Cisco and CISA flagged active exploitation of CVE-2026-20079, a critical authentication bypass in Cisco Secure Firewall Management Center allowing remote, unauthenticated attackers to run malicious scripts and gain root access via crafted HTTP requests. Cisco patched the flaw in early March and added IoCs in late July, but confirmed active exploitation in its September 9 advisory; CISA added it to the KEV catalog requiring federal remediation by September 12. Talos identified three activity clusters exploiting CVE-2026-20079 and CVE-2026-20316, including state-sponsored and financially motivated actors, and this is the third FMC vulnerability in KEV this year after CVE-2026-20316 and CVE-2026-20131.
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China-Linked Hackers Exploit Chrome and Windows Zero-Days in BlueMoon Attacks
China-linked clusters deploy the BlueMoon kit chaining Chrome V8 CVE-2026-85046 and Windows LPE CVE-2026-85880 in espionage campaigns.
Proofpoint researchers identified BlueMoon, an exploit kit combining a V8 type-confusion RCE (CVE-2026-85046), a V8 sandbox escape, and a Windows kernel privilege-escalation flaw (CVE-2026-85880), first observed August 28, 2026. At least four clusters adopted it, led by TA412 (also tracked as APT31/Violet Typhoon) and followed by UNK_LateNight, UNK_DoubleCheck, and UNK_QuietRacket, targeting aerospace, manufacturing, government, consulting, and financial sectors. The kit exploited a nearly four-week patch gap between the public Chromium commit (August 7) and stable rollout (September 3). TA412 delivered the GemStone Chrome extension masquerading as a Gemini companion, while other clusters deployed ShadowPad via DLL sideloading, a Rust loader, and DoH-based C2.
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U.S. CISA adds Cisco Secure Email Gateway flaw to its Known Exploited Vulnerabilities catalog
CISA added actively exploited Cisco Secure Email Gateway zero-day CVE-2026-76461 (CVSS 9.8) to KEV; federal agencies must patch by September 17, 2026.
CISA added CVE-2026-76461 (CVSS 9.8), a critical zero-day in Cisco AsyncOS for Cisco Secure Email Gateway, to its Known Exploited Vulnerabilities catalog. The flaw stems from insufficient validation in email parsing, letting an unauthenticated remote attacker send a crafted email with malicious SQL statements to achieve arbitrary command execution with root privileges. Cisco confirmed active exploitation in the wild, notes no workarounds exist, and recommends checking mail_logs for suspicious SQL statements like 'COPY.*TO PROGRAM' on every cluster device. Under BOD 22-01, FCEB agencies must remediate by September 17, 2026.
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Cisco Warns of Ongoing Exploitation of Critical Email Gateway Zero-Day
Cisco Secure Email Gateway zero-day CVE-2026-76461 (CVSS 9.8) is actively exploited for root command execution; CISA added it to KEV.
Cisco disclosed critical zero-day CVE-2026-76461 (CVSS 9.8) in Secure Email Gateway, remotely exploitable without authentication via crafted emails containing malicious SQL statements, leading to arbitrary command execution with root privileges. The flaw affects physical and virtual appliances regardless of configuration and has no workarounds. Cisco PSIRT confirmed active exploitation, and CISA added the CVE to its KEV catalog on September 14 with a federal remediation deadline of September 17. Admins should review mail_logs for suspicious SQL statements such as 'COPY.*TO PROGRAM'.
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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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Four Nation-State Actors Used the Same Chrome Zero-Day Exploit Kit Within 12 Days
Proofpoint reports four nation-state actors, mostly China-nexus, adopted the BlueMoon Chrome and Windows zero-day exploit kit within 12 days, targeting US organizations.
Proofpoint tracked an exploit kit dubbed BlueMoon that chains CVE-2026-85046, a Chrome V8 type-confusion bug, with an unnamed V8 sandbox escape and CVE-2026-85880, a Windows kernel privilege escalation using ALPC and the Windows Notification Facility. The first observed use was by China-nexus TA412 (APT31, Violet Typhoon, JungleBamboo) on August 28, 2026 against US NGOs, mining companies, and commodity trading firms, followed by UNK_LateNight targeting US aerospace and defense companies on September 2. Both V8 bugs were patch-gap zero-days: the fix was committed to Chromium on August 7 but reached stable Chrome on September 3, enabling rapid weaponization from public patches. TA412's post-exploitation payload, GemStone, is a malicious browser extension posing as an AI-powered Google Gemini companion that captures keystrokes, cookies, screenshots, and browsing history via a Cloudflare Worker C2.
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