Google Chrome 153 Released With 230 Security Fixes and Zero-Day Exploited in the Wild
Google released Chrome 153 with 230 security fixes, patching CVE-2026-87491, a V8 out-of-bounds write zero-day actively exploited in the wild.
Google shipped Chrome 153 (153.0.8010.36/.37) for Windows, macOS, and Linux with 230 security fixes, including CVE-2026-87491, a medium-severity V8 out-of-bounds write being exploited in the wild. The release also fixes five critical vulnerabilities: four in WebGL (two use-after-frees, an out-of-bounds write, a buffer overflow) and one use-after-free in Cast. High-severity V8 use-after-free and type-confusion defects are among the fixes, and Google has restricted technical details until most users are patched. Administrators should verify deployed versions on managed endpoints, as Chrome-derived browsers may follow different patch schedules.
Microsoft fixes record 964 flaws, including 2 exploited zero-days
Microsoft's September Patch Tuesday fixes a record 964 CVEs, including two actively exploited Windows privilege-escalation zero-days, CVE-2026-81963 and CVE-2026-85880.
Microsoft's September 2026 Patch Tuesday addresses 964 customer-patchable CVEs (104 Critical, 860 Important), the largest release on record, out of 974 total listed. Two actively exploited zero-days are fixed: CVE-2026-81963, a link-following elevation-of-privilege flaw in the Windows Update Stack, and CVE-2026-85880, a Windows ALPC heap overflow enabling AppContainer sandbox escape, both with CVSS 7.8. Both zero-days were exploited before a patch was available and grant SYSTEM-level access after an initial foothold. The release also includes high-severity RCE fixes for Windows DNS Server, Remote Desktop Services, Exchange Server, SharePoint, and SQL Server.
CISA Adds Exploited MikroTik RouterOS Flaws to Security Alert
CISA added two actively exploited MikroTik RouterOS flaws, CVE-2026-67277 and CVE-2026-86060, to its KEV catalog with a September 13 mitigation deadline.
CISA added CVE-2026-67277 and CVE-2026-86060 in MikroTik RouterOS to the Known Exploited Vulnerabilities catalog on September 10, giving federal agencies until September 13 to apply vendor mitigations. CVE-2026-67277 is a missing-authentication flaw (CWE-306) in the bandwidth-test (btest) service that can expose kernel memory and cause denial of service; CVE-2026-86060 (CWE-88) lets attackers manipulate the trusted RouterOS policy mask for privilege escalation. CISA designated CVE-2026-86060 as requiring forensic triage under Binding Operational Directive 26-04, meaning organizations should hunt for compromise indicators, not just patch. Compromised routers could have altered routing rules, persistence, traffic interception, or use as pivots into internal networks.
Threat Brief: OWASSRF Vulnerability Exploitation
Unit 42 details active exploitation of Exchange SSRF flaws CVE-2022-41080/CVE-2022-41082 via the OWASSRF method, deploying the SilverArrow PowerShell backdoor.
Unit 42 documents OWASSRF, an exploit chain combining CVE-2022-41080 and CVE-2022-41082 to achieve remote code execution on Microsoft Exchange via Outlook Web Access, bypassing Microsoft's ProxyNotShell mitigations. Active exploitation was observed in late November and early December 2022, affecting at least eight organizations. Attackers authenticated to Exchange, then executed a PowerShell backdoor tracked as SilverArrow to create admin accounts, install AnyDesk, tunnel RDP via PuTTY Link, and dump LSASS memory for credential theft. Exploitation is isolated rather than mass-scale because authentication is required.
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.
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.
Hackers Are Probing PaperCut Servers, and 47% Still Have No Patch
PaperCut pre-auth RCE CVE-2026-81578 actively exploited; 47% of tracked installs unpatched and exposed to remote code execution.
Huntress confirmed active exploitation of a pre-authentication RCE flaw in PaperCut (CVE-2026-81578), chainable with CVE-2026-82078 to achieve SYSTEM-level code execution via PaperCut's Application Server. Observed attacks focused on short reconnaissance (whoami, ver, tasklist) with no persistence, but a malicious Java class dropping into the installation directory leaves the jdbc:derby:memory:pwn breadcrumb. Roughly 47% of ~2,500 tracked installations run version 23 or earlier with no patch yet available.
Attackers Chain Two PaperCut Flaws to Execute Code Without Authentication
Attackers chain PaperCut NG/MF flaws CVE-2026-81578 and CVE-2026-82078 for unauthenticated RCE; exploitation observed and a second emergency patch issued.
Two flaws in PaperCut NG and MF — CVE-2026-81578 (CVSS 8.8, improper access control enabling auth bypass) and CVE-2026-82078 (CVSS 9.4, unsafe dynamic class loading) — are being chained for unauthenticated remote code execution. Huntress observed limited exploitation on two customer environments, including Base64-encoded commands, 'whoami & ver' fingerprinting, SimpleHelp execution, and AnyDesk installation for persistence. PaperCut released a second emergency patch for v24, v25, and v26, but watchTowr reports additional patch bypasses may still affect the latest version. Shared IoCs include crafted jdbc strings in server.log and attacker-written .class/.cmd files.
CISA Adds 5 Actively Exploited Artifactory, ScreenConnect, and RouterOS Flaws to KEV
CISA added five actively exploited JFrog Artifactory, ConnectWise ScreenConnect, and MikroTik RouterOS flaws to its KEV catalog.
CISA added five actively exploited vulnerabilities to the KEV catalog: CVE-2026-42016 and CVE-2026-42018 in JFrog Artifactory, CVE-2026-84869 in ConnectWise ScreenConnect (CVSS 9.9), and CVE-2026-67277 and CVE-2026-86060 in MikroTik RouterOS. The Artifactory bugs are chained with CVE-2026-82329 to gain administrative control, deploy malicious Groovy plugins, and install Rust-based backdoors. CERT Polska dubbed the RouterOS chain 'MikroTrick'; FCEB agencies must patch between September 13 and 25, 2026.