{"id":"CVE-2021-25900","aliases":["GHSA-43w2-9j62-hq99","RUSTSEC-2021-0003"],"url":"https://o3.security/vulnerability/CVE-2021-25900","summary":"Buffer overflow in SmallVec::insert_many","details":"A bug in the SmallVec::insert_many method caused it to allocate a buffer that was smaller than needed. It then wrote past the end of the buffer, causing a buffer overflow and memory corruption on the heap. This bug was only triggered if the iterator passed to insert_many yielded more items than the lower bound returned from its size_hint method.\n\nThe flaw was corrected in smallvec 0.6.14 and 1.6.1, by ensuring that additional space is always reserved for each item inserted. The fix also simplified the implementation of insert_many to use less unsafe code, so it is easier to verify its correctness.","published":"2021-01-26T18:16:22.270Z","modified":"2026-11-11T02:45:09.133057920Z","cvss":{"score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":{"score":0.01666,"percentile":0.75604,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"crates.io","name":"smallvec","fixedVersion":"0.6.14"},{"ecosystem":"crates.io","name":"smallvec","fixedVersion":"1.6.1"}],"fix":{"url":"https://github.com/servo/rust-smallvec/commit/5757ac500d4e544485d796b542e4e589749c291b","label":"servo/rust-smallvec@5757ac5"},"references":[{"type":"FIX","url":"https://rustsec.org/advisories/RUSTSEC-2021-0003.html"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-25900"},{"type":"WEB","url":"https://github.com/servo/rust-smallvec/issues/252"},{"type":"WEB","url":"https://github.com/servo/rust-smallvec/commit/5757ac500d4e544485d796b542e4e589749c291b"},{"type":"WEB","url":"https://github.com/servo/rust-smallvec/commit/9998ba0694a6b51aa6604748b00b6a98f0a0039e"},{"type":"PACKAGE","url":"https://github.com/servo/rust-smallvec"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-11-11T02:45:09.133057920Z"}}