{"id":"CVE-2020-36208","aliases":["GHSA-3jc5-5hc5-33gj","RUSTSEC-2020-0101"],"url":"https://o3.security/vulnerability/CVE-2020-36208","summary":"Data races in conquer-once","details":"Affected versions of conquer-once implements Sync for its OnceCell type without restricting it to Sendable types.\n\nThis allows non-Send but Sync types such as MutexGuard to be sent across threads leading to undefined behavior and memory corruption in concurrent programs.\n\nThe issue was fixed by adding a Send constraint to OnceCell.","published":"2021-01-26T18:15:55.897Z","modified":"2026-07-09T00:37:16.594596Z","cvss":{"score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":{"score":0.00428,"percentile":0.35432,"asOf":"2026-08-25"},"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"crates.io","name":"conquer-once","fixedVersion":"0.3.2"}],"fix":null,"references":[{"type":"EVIDENCE","url":"https://rustsec.org/advisories/RUSTSEC-2020-0101.html"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2020-36208"},{"type":"WEB","url":"https://github.com/oliver-giersch/conquer-once/issues/3"},{"type":"PACKAGE","url":"https://github.com/oliver-giersch/conquer-once"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-09T00:37:16.594596Z"}}