Google Brotli Unchecked Return Value Vulnerability (CVE-2026-111497) is being actively exploited, CISA warns
CISA added CVE-2026-111497 (Google Brotli) to its Known Exploited Vulnerabilities catalog on October 27, 2026, which means there is reliable evidence of exploitation in the wild. Google Brotli contains an unchecked return value vulnerability that allows a remote unauthenticated attacker to corrupt adjacent decoder state memory, disclose sensitive memory contents, cause a denial of service, or potentially execute…
Excerpt from the primary source: CISA Known Exploited Vulnerabilities
Who is affected
Security professionals
Affected technology: Brotli
Why it matters
CISA lists this as exploited in the wild. Unpatched affected systems are exposed to active attacks now.
Automated: stated only from CISA listings and the exploitation evidence in the sources below.
What you should do · Act now
Treat this as an emergency. Identify every system running the affected products, apply the vendor's fix or published mitigations immediately, and check for signs of compromise. Patching alone does not remove an attacker who already got in.
CISA's required action for CVE-2026-111497: "Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines." US federal civilian agencies must comply by November 10, 2026.
Automated guidance based on this story's classification. Check the linked advisories for specifics.
Sources
We link to original and authoritative sources. Headlines and excerpts belong to their publishers.
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