{"id":"CVE-2020-2102","aliases":["BIT-jenkins-2020-2102","GHSA-fj6f-6933-839j"],"url":"https://o3.security/vulnerability/CVE-2020-2102","summary":"Non-constant time HMAC comparison","details":"Jenkins 2.218 and earlier, LTS 2.204.1 and earlier does not use a constant-time comparison when checking whether two HMACs are equal. This could potentially allow attackers to use statistical methods to obtain a valid HMAC for an attacker-controlled input value.\n\nJenkins 2.219, LTS 2.204.2 now uses a constant-time comparison when validating HMACs.","published":"2020-01-29T16:15:12.303Z","modified":"2026-10-24T10:30:51.595016237Z","cvss":{"score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N"},"epss":{"score":0.01397,"percentile":0.70598,"asOf":"2026-09-04"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Maven","name":"org.jenkins-ci.main:jenkins-core","fixedVersion":"2.204.2"},{"ecosystem":"Maven","name":"org.jenkins-ci.main:jenkins-core","fixedVersion":"2.219"}],"fix":{"url":"https://github.com/jenkinsci/jenkins/commit/6f35dbb939ebe947bdb1979010b208480f1d0e31","label":"jenkinsci/jenkins@6f35dbb"},"references":[{"type":"ADVISORY","url":"http://www.openwall.com/lists/oss-security/2020/01/29/1"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHBA-2020:0402"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHBA-2020:0675"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2020:0681"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2020:0683"},{"type":"ADVISORY","url":"https://jenkins.io/security/advisory/2020-01-29/#SECURITY-1660"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2020-2102"},{"type":"WEB","url":"https://github.com/jenkinsci/jenkins/commit/6f35dbb939ebe947bdb1979010b208480f1d0e31"},{"type":"PACKAGE","url":"https://github.com/jenkinsci/jenkins"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-24T10:30:51.595016237Z"}}