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CVE-2026-111497

Critical 9.8 Exploited in the wild (KEV)

Confirmed active exploitation — CISA KEV catalog

Name
Google Brotli Unchecked Return Value Vulnerability
Added to catalog
Remediation due date (US federal)
Required action
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.

Description

A buffer overflow vulnerability in the Brotli decoder (c/dec/decode.c) in Google Brotli versions 1.0.3 through 1.2.0 on all platforms allows a remote unauthenticated attacker to corrupt adjacent decoder state memory, disclose sensitive memory contents, cause a denial of service, or potentially execute arbitrary code using a crafted Brotli-compressed stream. Users need to update any Brotli libraries or binaries between 1.0.3 through 1.2.0 to the latest available version: 1.0.10 or 1.1.1 or 1.2.1.

Metrics

CVSS 3.1
9.8 (CRITICAL) Score source: NVD CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 4.0
9.2 (CRITICAL) Score source: CNA CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS — exploit probability
83% (percentile: 100) as of 1 November 2026
CWE
CWE-252, CWE-787

Affected products

google: brotli; nodejs: node.js; python-hyper: brotlicffi; microsoft: .net; debian: debian linux; istio: istio; anthropic: bun; envoyproxy: envoy; tianocore: edk2; google: woff2; duckdb: duckdb; clickhouse: clickhouse; apache: arrow; mcmilk: 7-zip-zstd; 7-zip: p7zip

References