{"id":"GHSA-xrf2-5r3p-5wgj","summary":"libcrux: Panic in Signature Hint Decoding During Verification","details":"During ML-DSA verification the serialized hint values are decoded as specified in algorithm 22 `HintBitUnpack` of [FIPS 204, subsection 7.1](https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.204.pdf#%5B%7B%22num%22%3A120%2C%22gen%22%3A0%7D%2C%7B%22name%22%3A%22FitH%22%7D%2C657%5D). The algorithm requires that the cumulative hint counters per row of the hint vector are strictly increasing and below a maximum value which depends on the choice of ML-DSA parameter set (line 4).\n\nIn libcrux-ml-dsa, hint decoding did not check the boundedness of the cumulative hint counter of the last row of the hint vector.\n\n## Impact\nA manipulated invalid hint can cause an out-of-bounds memory access since the hint decoding logic may attempt to read outside the bounds of the serialized signature, causing a runtime panic.\n\n## Mitigation\nStarting from version `0.0.8`, hint decoding will check the cumulative hint counter of the last row as well.","aliases":["RUSTSEC-2026-0076"],"modified":"2026-03-27T06:11:21.325253Z","published":"2026-03-26T17:58:16Z","database_specific":{"cwe_ids":["CWE-125","CWE-1285"],"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-03-26T17:58:16Z","nvd_published_at":null},"references":[{"type":"WEB","url":"https://github.com/cryspen/libcrux/pull/1348"},{"type":"PACKAGE","url":"https://github.com/cryspen/libcrux"},{"type":"WEB","url":"https://rustsec.org/advisories/RUSTSEC-2026-0076.html"}],"affected":[{"package":{"name":"libcrux-ml-dsa","ecosystem":"crates.io","purl":"pkg:cargo/libcrux-ml-dsa"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.0.8"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-xrf2-5r3p-5wgj/GHSA-xrf2-5r3p-5wgj.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"}]}