Security Affairs newsletter Round 594 by Pierluigi Paganini – INTERNATIONAL EDITION
Weekly Security Affairs newsletter aggregates top stories including Cisco FMC exploitation, Qilin ransomware, Chrome zero-days, and Berlin leak.
Pierluigi Paganini's Security Affairs newsletter Round 594 (International Edition) rounds up the week's security headlines. Topics include attackers exploiting a critical Cisco FMC flaw to deploy Qilin ransomware, SonicWall mass exploitation linked to a UK council attack, multiple CISA KEV additions, Chrome zero-days used by four nation-state actors, a $320 million Liquid Network theft, and a Berlin ransomware data leak. It also covers AI security items such as agent sandbox failures and distillation campaigns by Chinese AI firms.
BlueMoon Exploit Kit Chains Recent Chrome, Windows Zero-Days
Proofpoint reports multiple espionage groups rapidly adopting BlueMoon, a new exploit kit chaining Chrome and Windows zero-days.
Proofpoint identified a new exploit kit, BlueMoon, chaining two Chrome V8 zero-days (CVE-2026-85046, CVE-2026-87491) with a Windows ALPC privilege escalation zero-day (CVE-2026-85880), all patched between September 3 and September 2026 Patch Tuesday. China-linked Violet Typhoon (APT31) first used it on August 28 against US NGOs and mining/commodity trading firms; UNK_LateNight, UNK_DoubleCheck, and UNK_QuietRacket adopted it within days against targets in the US, Vietnam, Indonesia, and Singapore. The kit exploits the V8 defects for sandbox escape, fingerprints the host, and injects a CreateProcess stub into the Chrome broker process to download and execute a payload via curl. Development artifacts suggest the kit's creators may have used AI to build it, potentially lowering the barrier to exploit development.
Serial Microsoft 0-day hunter drops yet another Defender exploit
Researcher Nightmare Eclipse released ShieldCrash, a Microsoft Defender zero-day PoC that bypasses September patches and reads files as SYSTEM.
Zero-day researcher Nightmare Eclipse (MSNightmare) published ShieldCrash, their 11th Microsoft zero-day, a proof-of-concept bypass of the ShieldBreak patch (CVE-2026-69414), which itself had bypassed the fix for RoguePlanet (CVE-2026-50656). ShieldCrash works on Windows 10, Windows 11, and Windows Server systems that have applied the September 2026 patches and allows arbitrary file reads as SYSTEM, though not arbitrary writes or a full SYSTEM shell. Microsoft has not said when it plans to patch the issue. The researcher recently also released zero-days affecting CrowdStrike Falcon (FalconFlank), Kaspersky endpoint antivirus (HardBreacher, patched), and Gen Digital's Avast (PrettyPrague).
September 2026 Patch Tuesday: 974 Flaws, 2 Zero-Days
Microsoft's September 2026 Patch Tuesday fixes 974 vulnerabilities, including two actively exploited Windows elevation-of-privilege zero-days added to CISA's KEV catalog.
Microsoft's September 2026 Patch Tuesday release addresses 974 vulnerabilities, one of the largest monthly batch sizes. Two of the flaws are actively exploited zero-days, and both are Windows elevation-of-privilege vulnerabilities. CISA added both zero-days to its Known Exploited Vulnerabilities catalog, subjecting them to federal patching deadlines. SOCRadar's report provides a breakdown of the patched vulnerabilities by category.
Microsoft’s Biggest Patch Tuesday: 974 CVEs, 2 Zero-Days and 20 Wormable Bugs
Microsoft's record September 2026 Patch Tuesday fixes 974 CVEs, including two exploited Windows privilege-escalation zero-days and 20 wormable bugs.
Microsoft's September 2026 Patch Tuesday fixes a record 974 CVEs, including two actively exploited zero-days: CVE-2026-85880, an ALPC heap buffer overflow, and CVE-2026-81963 in the Windows Update Stack, both CVSS 7.8 local privilege escalations. It also addresses an unauthenticated Exchange RCE (CVE-2026-55007) triggered by Visio attachment content indexing under memory pressure, an RDP use-after-free (CVE-2026-69525, CVSS 9.8), and 20 wormable flaws in DNS, DHCP, SMB, Active Directory, and other components. ZDI attributed the rising volume partly to AI-assisted vulnerability discovery, noting no corresponding spike in active exploits yet.
Microsoft Patches Record 974 Flaws, Including Two Exploited Windows Zero-Days
Microsoft's September Patch Tuesday fixed a record 974 flaws, including two Windows privilege-escalation zero-days actively exploited and added to CISA's KEV catalog.
Microsoft's September 2026 Patch Tuesday addressed a record 974 vulnerabilities (999 including 25 non-Microsoft CVEs), with over 110 rated critical; 723 affect Windows and 111 affect Office. Two Windows privilege-escalation zero-days are actively exploited: CVE-2026-85880, an ALPC heap-based buffer overflow, and CVE-2026-81963, an improper link resolution flaw in the Windows Update Stack, both allowing attackers to gain SYSTEM privileges. CISA added both flaws to its KEV catalog, giving federal civilian agencies until September 22, 2026 to apply fixes. Volexity, Proofpoint, MSTIC, and independent researchers were credited with the reports; notable additional fixes include network-reachable RCEs in Exchange, SharePoint, SQL Server, Remote Desktop Services, DNS, and DHCP.
StyleSmuggler (CVE-2026-75650): Frequently asked questions about Adobe Commerce and Magento zero-day
Critical unauthenticated RCE zero-day CVE-2026-75650 (StyleSmuggler) in Adobe Commerce and Magento is actively exploited; Adobe shipped hotfix VULN-39341 on September 7.
CVE-2026-75650 is a CVSS 10.0 unauthenticated remote code execution flaw in Adobe Commerce 2.4.4-2.4.9, Adobe Commerce B2B 1.3.3-1.5.3, and Magento Open Source 2.4.6-2.4.9, exploited via malicious style properties that inject PHP code executed through a transactional email template. Active exploitation began September 4, 2026, three days before Adobe released Hotfix VULN-39341 (APSB26-146) on September 7, with multiple victim stores confirmed by Sansec and Disrex across at least two distinct campaigns. Attackers deploy a persistent implant at ~/.local/share/.gvfsd/gvfsd-user masquerading as kworker, fc-cache, or chronyd, sustained by a cron job, while a second operator dropped a PHP web shell in product image caches. Tenable classified it as a Vulnerability of Interest; it is not yet in CISA KEV as of September 8, and Adobe also recommends rotating encryption keys and all protected credentials.
StyleSmuggler: The Magento Zero-Day Behind New Store Attacks
Sansec reports actively exploited Magento/Adobe Commerce zero-day StyleSmuggler enabling unauthenticated RCE and Rust backdoor installation on fully patched stores since September 4.
Sansec discovered StyleSmuggler, an unpatched zero-day in Magento Open Source and Adobe Commerce, affecting all current versions including 2.4.7, 2.4.8 and 2.4.9, with attacks observed since September 4. The two-stage attack poisons Magento's template system via the styles property and executes the injected PHP during 'Payment Transaction Failed Reminder' email rendering, working even when email delivery fails and when sessions are moved to Redis. Successful compromise installs a lightweight Rust backdoor disguised as fc-cache or chronyd that beacons every 60 seconds with 48-byte UDP packets to NTP port 123 at ntp.timesync.to. A second attacker deployed a PHP web shell in product-image cache directories, hidden behind 404 responses unless a correct X-Cache-Token header is present.
SonicWall SMA 1000 Zero-Days Enable Unauthenticated RCE
New SonicWall SMA 1000 zero-days enable unauthenticated remote code execution, with exploitation observed following earlier summer attacks on other SonicWall edge zero-days.
Zero-day vulnerabilities in SonicWall's SMA 1000 secure access appliances allow unauthenticated remote code execution, and exploitation activity is being observed. This follows attacks earlier in the summer that abused two other zero-day vulnerabilities in SonicWall edge devices. Internet-facing appliances used for remote access make this an urgent patching priority for defenders.
PaperCut Zero-Day Under Active Attack: Emergency Patch Released
PaperCut warns that a zero-day in NG and MF print management products is being actively exploited, shipping emergency patches with no CVE assigned yet.
PaperCut Software confirmed active exploitation of a zero-day affecting PaperCut NG and MF, with confirmed customer incidents, and released emergency patches on Friday ahead of technical details or a CVE assignment. The company urges customers to restrict web access to trusted IP addresses, disconnect application servers from the internet, and watch for indicators including tampered or truncated server.log files, database error strings, and suspicious activity involving pc-app.exe. The article recalls the May 2023 exploitation of CVE-2023-27350 and CVE-2023-27351 by the financially motivated Lace Tempest group, a Clop ransomware RaaS affiliate, though no attacker attribution has been given for the current campaign.
Google researchers uncover criminal zero-day exploit likely built with AI
Google links a likely LLM-built criminal zero-day for an open-source admin tool to planned mass exploitation and maps AI-assisted threats.
Google Threat Intelligence Group linked a zero-day exploit for a popular open-source web-based administration tool, enabling 2FA bypass with valid credentials via a semantic logic error, to a criminal group, citing educational docstrings, a hallucinated CVSS score, and textbook Python as signs of LLM authorship; the vendor was notified before a planned mass exploitation campaign. The report also details Russia-nexus malware families CANFAIL and LONGSTREAM using AI-generated decoy code, the PROMPTSPY Android backdoor driving the UI through the Gemini API, APT27 using Gemini to build relay tooling, and the TeamPCP (UNC6780) supply chain compromise of LiteLLM and Trivy repositories that planted the SANDCLOCK credential stealer.