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Brotli2Shell: Critical Vulnerability in Google Brotli (CVE-2026-111497)

A critical security vulnerability tracked as CVE-2026-111497, also known as Brotli2Shell, has been discovered in Google’s Brotli decompression library.

The flaw is an out-of-bounds write vulnerability that can lead to memory corruption, information disclosure, denial of service, and potentially arbitrary code execution when processing malicious Brotli-compressed data.

The vulnerability affects multiple platforms and software products, including Node.js, .NET, PHP (Windows builds), and other applications using vulnerable Brotli versions.

Affected Brotli versions: 1.0.3 through 1.2.0.

Fixed versions:

  • Brotli 1.0.10

  • Brotli 1.1.1

  • Brotli 1.2.1

Administrators should update affected libraries and applications, rebuild vulnerable containers where necessary, and restart affected services.

Read our technical analysis and mitigation guide:

How to Fix the Critical Brotli Vulnerability (CVE-2026-111497)

CVE: CVE-2026-111497
Reference: Google Brotli Security Fixes