ZeroHour

Source: Malwarebytes Labs

3 stories in the last 7d

BlueMoon exploit kit turns Chrome and Windows flaws into attacks

Proofpoint documents BlueMoon exploit kit used by four espionage groups to chain Chrome V8 and Windows flaws via phishing, all now in CISA's KEV.

Proofpoint identified a shared Chrome and Windows exploit kit, BlueMoon, used by four espionage groups against Chrome on Windows within days of one another. Attacks began with phishing emails leading to web pages that exploited two Chrome V8 vulnerabilities, followed by a Windows flaw to escape browser protections and gain higher privileges. The Chrome flaws were patched in Stable on September 3 and 8, 2026, the Windows flaw was fixed in September Patch Tuesday, and all three were actively exploited and added to CISA's KEV catalog. Researchers found clues, but no conclusive evidence, that the kit was developed with AI assistance.

Malwarebytes Labsupdated · 12h agofirst · 5d agoExploit / PoC in the wild 20 sources1

Update Chrome now to protect against an actively exploited vulnerability

Google shipped Chrome 153.0.8010.36/.37 fixing 230 flaws including actively exploited V8 out-of-bounds write CVE-2026-87491 enabling sandboxed code execution.

Chrome stable channel updated to 153.0.8010.36/.37 for Windows and Mac and 153.0.8010.36 for Linux, including 230 security fixes. CVE-2026-87491 is an out-of-bounds write in Chrome's V8 JavaScript engine that a crafted HTML page can exploit to execute arbitrary code inside the browser sandbox; Google rates it medium severity, but it is confirmed as actively exploited. The update also fixes five Critical vulnerabilities, four of which were found in WebGL. Users should update via Settings > About Chrome and restart the browser.

Malwarebytes Labs · 5d agoExploit / PoC in the wild 2 sourcesCVE-2026-874911

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.