{"id":"CVE-2026-54431","aliases":["AZL-91682","DEBIAN-CVE-2026-54431","EUVD-2026-41277","GHSA-3pf6-g4x4-jm46","UBUNTU-CVE-2026-54431"],"status":"published","title":"Improper Data Validation in liboauth2","description":"In liboauth2 the Demonstrating Proof-of-Possession (DPoP) verifier accepts a proof whose JSON Web Key (jwk) header contains private key material. RFC 9449 section 4.3 step 7 requires the verifier to reject such a proof but oauth2_token_verify() function returns success for a malformed DPoP proof that embeds the private Elliptic Curve (EC) key in the header.\n\nThis issue was fixed in version 2.3.0","severity":{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00178,"percentile":0.07462,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-358"],"published":"2026-07-02T10:30:57Z","modified":"2026-11-05T05:36:30Z","fixes":[{"ecosystem":"Debian:14","package":"liboauth2","fixed_in":["2.3.0-1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Azure Linux:3","package":"liboauth","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"1.0.3-15"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"liboauth2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.4.5.4-1","1.5.1-1","1.5.1-2","1.5.1-3","1.5.2-1","1.6.0-1","1.6.1-1","1.6.2-1","1.6.3-1","2.0.0-1","2.1.0-1","2.1.0-2","2.1.1-1","2.2.0-1","2.2.0-2","2.2.1-1","2.3.0-1","2.4.0-1"]},{"source":"osv","ecosystem":"Debian:13","package":"liboauth2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.1.0-2","2.1.1-1","2.2.0-1","2.2.0-2","2.2.1-1","2.3.0-1","2.4.0-1"]},{"source":"osv","ecosystem":"Debian:14","package":"liboauth2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.0-1"}]}],"versions":["2.1.0-2","2.1.1-1","2.2.0-1","2.2.0-2","2.2.1-1"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"liboauth2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.4.0.1-1","1.4.3.2-1","1.4.3.2-2","1.4.3.2-3","1.4.3.2-3ubuntu1","1.4.3.2-4","1.4.4-1"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"liboauth2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.5.1-3","1.5.2-1","1.6.0-1","1.6.0-1build1","1.6.0-1build3","1.6.0-1build4"]},{"source":"osv","ecosystem":"Ubuntu:25.10","package":"liboauth2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.1.0-1","2.1.0-2"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"liboauth2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.2.0-2ubuntu1","2.4.0-1"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"liboauth2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.1.0-2","2.1.1-1","2.2.0-1","2.2.0-2ubuntu1"]}],"products":[{"vendor":"openidc","product":"liboauth2"}],"references":[{"url":"https://cert.pl/en/posts/2026/07/CVE-2026-54430","tags":["third-party-advisory","advisory","report"]},{"url":"https://github.com/OpenIDC/liboauth2","tags":["product","package","report"]},{"url":"https://github.com/OpenIDC/liboauth2/commit/c0b57152ed6a0af33aeb04a60bd7f5bff5ab8800","tags":["issue-tracking","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54431","tags":["web","advisory"]},{"url":"https://github.com/advisories/GHSA-3pf6-g4x4-jm46"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54431.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-54431","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-54431","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-54431","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-54431","title":"Improper Data Validation in liboauth2","description":"In liboauth2 the Demonstrating Proof-of-Possession (DPoP) verifier accepts a proof whose JSON Web Key (jwk) header contains private key material. RFC 9449 section 4.3 step 7 requires the verifier to reject such a proof but oauth2_token_verify() function returns success for a malformed DPoP proof that embeds the private Elliptic Curve (EC) key in the header.\n\nThis issue was fixed in version 2.3.0","status":"published","published":"2026-07-02T10:30:57.655Z","modified":"2026-07-02T12:16:41.569Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N","level":"medium","assessor":"cna"}],"cwes":["CWE-358"],"updated_at":"2026-11-02T13:37:58.613221Z"}],"euvd":[{"id":"EUVD-2026-41277","description":"In liboauth2 the Demonstrating Proof-of-Possession (DPoP) verifier accepts a proof whose JSON Web Key (jwk) header contains private key material. RFC 9449 section 4.3 step 7 requires the verifier to reject such a proof but oauth2_token_verify() function returns success for a malformed DPoP proof that embeds the private Elliptic Curve (EC) key in the header.\n\nThis issue was fixed in version 2.3.0","status":"published","published":"2026-07-02T10:30:57Z","modified":"2026-07-02T12:16:41Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"updated_at":"2026-11-02T18:20:18.134523Z"}],"ghsa":[{"id":"GHSA-3pf6-g4x4-jm46","title":"In liboauth2 the Demonstrating Proof-of-Possession (DPoP) verifier accepts a proof whose JSON Web...","description":"In liboauth2 the Demonstrating Proof-of-Possession (DPoP) verifier accepts a proof whose JSON Web Key (jwk) header contains private key material. RFC 9449 section 4.3 step 7 requires the verifier to reject such a proof but oauth2_token_verify() function returns success for a malformed DPoP proof that embeds the private Elliptic Curve (EC) key in the header.\n\nThis issue was fixed in version 2.3.0","status":"published","published":"2026-07-02T12:30:59Z","modified":"2026-07-02T12:31:03Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium"}],"cwes":["CWE-358"],"updated_at":"2026-11-02T15:09:10.929571Z"}],"nvd":[{"id":"CVE-2026-54431","description":"In liboauth2 the Demonstrating Proof-of-Possession (DPoP) verifier accepts a proof whose JSON Web Key (jwk) header contains private key material. RFC 9449 section 4.3 step 7 requires the verifier to reject such a proof but oauth2_token_verify() function returns success for a malformed DPoP proof that embeds the private Elliptic Curve (EC) key in the header.\n\nThis issue was fixed in version 2.3.0","status":"published","published":"2026-07-02T11:16:17.123Z","modified":"2026-10-25T21:10:00.77Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"}],"cwes":["CWE-358"],"updated_at":"2026-11-02T14:12:27.199837Z"}],"osv":[{"id":"CVE-2026-54431","title":"Improper Data Validation in liboauth2","description":"In liboauth2 the Demonstrating Proof-of-Possession (DPoP) verifier accepts a proof whose JSON Web Key (jwk) header contains private key material. RFC 9449 section 4.3 step 7 requires the verifier to reject such a proof but oauth2_token_verify() function returns success for a malformed DPoP proof that embeds the private Elliptic Curve (EC) key in the header.\n\nThis issue was fixed in version 2.3.0","status":"published","published":"2026-07-02T10:30:57.655Z","modified":"2026-10-28T10:52:04.556180329Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-358"],"updated_at":"2026-11-02T15:45:10.818486Z"},{"id":"DEBIAN-CVE-2026-54431","description":"In liboauth2 the Demonstrating Proof-of-Possession (DPoP) verifier accepts a proof whose JSON Web Key (jwk) header contains private key material. RFC 9449 section 4.3 step 7 requires the verifier to reject such a proof but oauth2_token_verify() function returns success for a malformed DPoP proof that embeds the private Elliptic Curve (EC) key in the header.  This issue was fixed in version 2.3.0","status":"published","published":"2026-07-02T11:16:17.123Z","modified":"2026-10-26T11:47:23.936429264Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium"}],"updated_at":"2026-11-02T15:45:57.236551Z"},{"id":"UBUNTU-CVE-2026-54431","description":"In liboauth2 the Demonstrating Proof-of-Possession (DPoP) verifier accepts a proof whose JSON Web Key (jwk) header contains private key material. RFC 9449 section 4.3 step 7 requires the verifier to reject such a proof but oauth2_token_verify() function returns success for a malformed DPoP proof that embeds the private Elliptic Curve (EC) key in the header. This issue was fixed in version 2.3.0","status":"published","published":"2026-07-02T11:16:00Z","modified":"2026-10-17T12:59:06.459516642Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"updated_at":"2026-11-02T16:56:41.382716Z"},{"id":"AZL-91682","title":"CVE-2026-54431 affecting package liboauth 1.0.3-15","description":"In liboauth2 the Demonstrating Proof-of-Possession (DPoP) verifier accepts a proof whose JSON Web Key (jwk) header contains private key material. RFC 9449 section 4.3 step 7 requires the verifier to reject such a proof but oauth2_token_verify() function returns success for a malformed DPoP proof that embeds the private Elliptic Curve (EC) key in the header.\n\nThis issue was fixed in version 2.3.0","status":"published","published":"2026-07-02T11:16:17Z","modified":"2026-11-05T05:36:30Z","updated_at":"2026-11-05T16:41:25.633663Z"}]}}