CVE-2026-111497

Critical

Google Brotli Unchecked Return Value Vulnerability

9.8 CVSS v3.1 CVSS v4.0: 9.2

Published: Oct 22, 2026
Updated: Oct 28, 2026
Vendor: Debian, Google, Microsoft, Nodejs, Python-hyper
Affected versions: See affected products
Weakness: CWE-252, CWE-787

Summary

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.

Severity

Critical (9.8)

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v4.0 (9.2)

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

Affected products

Google Brotli >= 1.0.3, < 1.0.10
Google Brotli >= 1.1.0, < 1.1.1
Google Brotli >= 1.2.0, < 1.2.1
Nodejs Node.js < 22.23.4
Nodejs Node.js >= 23.0.0, < 24.22.1
Nodejs Node.js >= 25.0.0, < 26.12.1
Python-hyper Brotlicffi < 1.2.1.0
Microsoft .net >= 8.0.0, < 8.0.33
Microsoft .net >= 9.0.0, < 9.0.22
Microsoft .net >= 10.0.0, < 10.0.14
Microsoft .net 11.0.0
Debian Debian Linux 12.0

Show 16 more

Istio Istio < 1.29.9
Istio Istio >= 1.30.0, < 1.30.6
Istio Istio >= 1.31.0, < 1.31.2
Anthropic Bun < 1.4.4
Envoyproxy Envoy < 1.37.8
Envoyproxy Envoy >= 1.38.0, < 1.38.6
Envoyproxy Envoy >= 1.39.0, < 1.39.3
Tianocore Edk2 <= 202608
Google Woff2
Duckdb Duckdb <= 2.0.0
Clickhouse Clickhouse <= 26.10.2.103
Apache Arrow <= 26.0.0
Apache Arrow 27.0.0
Mcmilk 7-zip-zstd <= 26.02-1.5.7-r2
7-zip P7zip <= 16.02
Andybalholm Brotli < 1.2.7

Exploitation status

Actively exploited

Listed in the CISA Known Exploited Vulnerabilities catalog on Oct 27, 2026. Federal remediation due: Nov 10, 2026.

Technical details

Technical analysis has not been written for this record yet.

Mitigation & remediation

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.