Brotli flaw reaches Node.js, Python and other software that decompresses untrusted data
CVE-2026-111497 is an out-of-bounds write in Google’s Brotli decoder, affecting versions 1.0.3 through 1.2.0. Researchers and vendors say software can be exposed when it decompresses attacker-controlled request bodies, downloaded responses or files; code execution has been demonstrated in a lab, but no attacks in the wild had been reported by 24 October. Fixes are available for Brotli, Node.js, Bun and Python packages, with other products and Linux distributions updating on their own schedules.
Bottom line — Patch every reachable decoder, including bundled copies, and restart running processes; Node.js fixes include 22.23.4 and 24.22.1.
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ByteMuni says the same decoder is bundled in Node.js, Bun and Python packages, and used in products including Envoy and curl.
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According to ByteMuni, Python clients such as requests and aiohttp can decode Brotli responses automatically when Brotli packages are installed.
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Google’s fixed Brotli releases are 1.0.10, 1.1.1 and 1.2.1; ByteMuni lists Bun 1.4.4 and Python Brotli 1.2.1 as fixes.
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ByteMuni reports that Envoy is affected only when its Brotli decompressor is configured; default Apache and Nginx do not decode Brotli request bodies.
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According to Mallory.ai, public exploit code had not achieved code execution on a stock Node.js build, while private lab demonstrations had succeeded.
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Brandefense says Debian 12 and 13 had shipped fixes by 24 October, while distribution status varied by release.