{"id":"RUSTSEC-2026-0076","summary":"Panic in Signature Hint Decoding During Verification","details":"During ML-DSA verification the serialized hint values are decoded as\nspecified in algorithm 22 `HintBitUnpack` of [FIPS 204, subsection\n7.1](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\nalgorithm requires that the cumulative hint counters per row of the\nhint vector are strictly increasing and below a maximum value which\ndepends on the choice of ML-DSA parameter set (line 4).\n\nIn libcrux-ml-dsa, hint decoding did not check the boundedness of the\ncumulative 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\nsince the hint decoding logic may attempt to read outside the bounds\nof the serialized signature, causing a runtime panic.\n\n## Mitigation\nStarting from version `0.0.8`, hint decoding will check the cumulative\nhint counter of the last row as well.","aliases":["GHSA-xrf2-5r3p-5wgj"],"modified":"2026-03-27T05:55:06Z","published":"2026-03-04T12:00:00Z","database_specific":{"license":"CC0-1.0"},"references":[{"type":"PACKAGE","url":"https://crates.io/crates/libcrux-ml-dsa"},{"type":"ADVISORY","url":"https://rustsec.org/advisories/RUSTSEC-2026-0076.html"},{"type":"WEB","url":"https://github.com/cryspen/libcrux/pull/1348"}],"affected":[{"package":{"name":"libcrux-ml-dsa","ecosystem":"crates.io","purl":"pkg:cargo/libcrux-ml-dsa"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0.0.0-0"},{"fixed":"0.0.8"}]}],"ecosystem_specific":{"affected_functions":null,"affects":{"os":[],"arch":[],"functions":["libcrux_ml_dsa::ml_dsa_44::verify","libcrux_ml_dsa::ml_dsa_65::verify","libcrux_ml_dsa::ml_dsa_87::verify"]}},"database_specific":{"categories":[],"cvss":"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","informational":null,"source":"https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2026-0076.json"}}],"schema_version":"1.7.5","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"}]}