Critical CVE-2026-111497 Out-of-Bounds Write Flaw in Google Brotli Decoder Impacts Broad Range of Environments
A critical vulnerability has been discovered in the Google Brotli decoder, a widely used component for handling compressed data in web communications and numerous other environments. The issue, identified as CVE-2026-111497, resides in the C-language implementation of the decoder and can trigger an out-of-bounds write when processing maliciously crafted Brotli-compressed input.
Successful exploitation may result in arbitrary code execution, sensitive information leakage, or denial-of-service conditions. The vulnerability received a CVSS v4.0 base score of 9.2, placing it in the highest severity category of Critical.
Google has published corrected releases of the library: version 1.2.1, 1.1.1, and 1.0.10. Node.js developers referenced the CVE in their update notes, while Microsoft delivered an out-of-band security update on October 25, 2026, that resolves the flaw within the .NET framework.
Security researchers and coordination centers including JPCERT/CC and JVN have issued alerts highlighting the broad potential impact on any system that processes Brotli-encoded data.
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