{"slug": "openai-found-a-critical-flaw-in-brotli-used-by-node-js-bun-and-envoy", "title": "OpenAI found a critical flaw in Brotli (used by Node.js, Bun and Envoy)", "summary": "OpenAI's red-teaming exercise uncovered a critical vulnerability in Brotli, the widely deployed compression library bundled into Node.js, Bun and Envoy, that allows unauthenticated remote code execution. An attacker can take over an unpatched server that accepts compressed input by sending malicious compressed data, or an unpatched client such as \"curl --compressed\" by replying with it, with no user account required. The root cause was fixed in Brotli's source code in February but was not known at the time to be a security vulnerability, and no newer Brotli release existed; OpenAI disclosed the flaw to Brotli and downstream projects including Node.js, which released or is releasing security updates, and Brotli cut new release versions and published a CVE.", "body_md": "During this red-teaming exercise, we also found a vulnerability that allows for unauthenticated remote code execution in Brotli, a widely-deployed compression library included in many pieces of software such as Node.js, Bun, and Envoy.\nThe flaw could let an attacker run their own code on affected systems by sending or replying with malicious compressed data, without any need to create a user account. That is, an unpatched server that accepts compressed input could be taken over by a malicious client, and an unpatched client that accepts compressed input (such as “curl --compressed”) could be taken over by a malicious server.\nThis root cause issue was actually fixed in the Brotli source code in February, but it wasn’t known at the time that it gave rise to a security vulnerability and there was no more recent release of Brotli. Since Brotli is built into other software, any software which includes this library needs to take the update too, followed by the users of that software. We disclosed the vulnerability to Brotli and other downstream projects such as Node.js, which released or are currently releasing security updates, and Brotli cut new release versions and published a CVE.\nMore details on the patch and mitigations below:", "url": "https://wpnews.pro/news/openai-found-a-critical-flaw-in-brotli-used-by-node-js-bun-and-envoy", "canonical_source": "https://twitter.com/OpenAI/status/2113766354386084338", "published_at": "2026-10-23 23:46:57+00:00", "updated_at": "2026-10-24 00:12:59.982628+00:00", "lang": "en", "topics": ["ai-safety", "ai-research", "developer-tools"], "entities": ["OpenAI", "Brotli", "Node.js", "Bun", "Envoy", "curl"], "also_reported_by": [], "alternates": {"html": "https://wpnews.pro/news/openai-found-a-critical-flaw-in-brotli-used-by-node-js-bun-and-envoy", "markdown": "https://wpnews.pro/news/openai-found-a-critical-flaw-in-brotli-used-by-node-js-bun-and-envoy.md", "text": "https://wpnews.pro/news/openai-found-a-critical-flaw-in-brotli-used-by-node-js-bun-and-envoy.txt", "jsonld": "https://wpnews.pro/news/openai-found-a-critical-flaw-in-brotli-used-by-node-js-bun-and-envoy.jsonld"}}