{"id":"RUSTSEC-2026-0348","aliases":["GHSA-h2v8-394m-p7vv"],"title":"Brotli certificate decompression can allocate up to 1 GiB before authentication","summary":"Brotli certificate decompression can allocate up to 1 GiB before authentication","severity":"low","cvss":3.7,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L","vendor":"rustls","product":"rustls","ecosystem":"rust","affected":["rustls >= 0.23.9, < 0.23.46"],"patched":["rustls 0.23.46"],"published":"2026-10-14","updated":"2026-10-14","sourceUpdated":"2026-10-14T13:30:02.480925286Z","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/RUSTSEC-2026-0348","references":[{"url":"https://crates.io/crates/rustls"},{"url":"https://rustsec.org/advisories/RUSTSEC-2026-0348.html"},{"url":"https://github.com/rustls/rustls/pull/3297"}],"tags":["osv","rust"],"ingestedAt":"2026-10-15T11:47:08.230Z","slug":"RUSTSEC-2026-0348","body":"## Overview\n\nThe built-in Brotli certificate decompressor (enabled by the non-default\n`brotli` crate feature) bounded the size of the decompressed output, but\naccepted a peer-selected history window. Brotli's large-window extension was\nenabled, so a five-byte header could cause an allocation of 1 GiB. A peer can\nabort a process whose allocator cannot satisfy that request.\n\nNo trusted certificate is required by the attacker. Affected configurations are:\n\n- clients that enable the `brotli` feature and connect to a malicious server, and\n- servers that enable the `brotli` feature and request client certificates.\n\nApplications that do not enable the `brotli` feature are not affected.\n\n## Affected packages\n\n- `rustls >= 0.23.9, < 0.23.46`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `rustls 0.23.46`","depth":"sunlit","depthScore":20,"depthScoreParts":{"impact":20.4,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}