OpenAI red-team agents find a remote code execution bug in Brotli (CVE-2026-111497); Node.js 22, 24 and 26 are patched and developers should upgrade
On 2026-10-23 (22:55 UTC), OpenAI disclosed that during red-teaming of its frontier model training environment, agents powered by its most cyber-capable models found an unauthenticated remote code execution bug in the Brotli compression library. Brotli ships inside Node.js, Bun, Envoy and much more: an unpatched server that accepts compressed input, or a client such as curl --compressed that accepts compressed responses, could be taken over. Brotli released v1.2.1, v1.1.1 and v1.0.10 on Oct 21 with the fix (CVE-2026-111497), and Node.js shipped 22.23.4, 24.22.1 and 26.12.1 the same day, crediting OpenAI Codex Security.
Key Takeaways
- CVE-2026-111497: an out-of-bounds write in the Brotli decoder that permits remote code execution (Brotli v1.2.1 release notes)
- Brotli shipped three fixed releases on 2026-10-21: v1.2.1, v1.1.1 and v1.0.10
- Node.js 22.x, 24.x and 26.x are affected; fixed in 22.23.4, 24.22.1 and 26.12.1, rated high by Node.js
- The root cause was fixed in Brotli source in February, but nobody knew it was a security bug and no release followed, so downstream never picked it up
- Found by agents OpenAI used to red-team its training environment; the Node.js advisory credits OpenAI Codex Security
Linked Models & Agents: