{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-54431","assignerOrgId":"4bb8329e-dd38-46c1-aafb-9bf32bcb93c6","state":"PUBLISHED","assignerShortName":"CERT-PL","dateReserved":"2026-06-15T13:08:01.057Z","datePublished":"2026-07-02T10:30:57.655Z","dateUpdated":"2026-07-02T12:16:41.569Z"},"containers":{"cna":{"providerMetadata":{"orgId":"4bb8329e-dd38-46c1-aafb-9bf32bcb93c6","shortName":"CERT-PL","dateUpdated":"2026-07-02T10:44:44.691Z"},"title":"Improper Data Validation in liboauth2","datePublic":"2026-07-02T00:00:00.000Z","problemTypes":[{"descriptions":[{"lang":"en","cweId":"CWE-358","description":"CWE-358 Improperly Implemented Security Check for Standard","type":"CWE"}]}],"affected":[{"vendor":"OpenIDC","product":"liboauth2","repo":"https://github.com/OpenIDC/liboauth2","programFiles":["src/dpop.c"],"programRoutines":[{"name":"_oauth2_dpop_parse_and_validate()"}],"versions":[{"status":"affected","version":"0","lessThan":"2.3.0","versionType":"semver"}],"defaultStatus":"unaffected"}],"descriptions":[{"lang":"en","value":"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","supportingMedia":[{"type":"text/html","base64":false,"value":"<span>In liboauth2 the Demonstrating Proof-of-Possession (DPoP) verifier accepts a proof whose JSON Web Key (jwk) header contains private key&nbsp;</span><span>material. RFC 9449 section 4.3 step 7 requires the verifier to reject&nbsp;</span><span>such a proof but</span><span>&nbsp;<i>oauth2_token_verify()</i> function returns success for a malformed DPoP&nbsp;</span><span>proof that embeds the private Elliptic Curve (EC) key in the header.<br><br></span>This issue was fixed in version 2.3.0"}]}],"tags":["x_open-source"],"references":[{"url":"https://cert.pl/en/posts/2026/07/CVE-2026-54430","tags":["third-party-advisory"]},{"url":"https://github.com/OpenIDC/liboauth2","tags":["product"]},{"url":"https://github.com/OpenIDC/liboauth2/commit/c0b57152ed6a0af33aeb04a60bd7f5bff5ab8800","tags":["issue-tracking"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"LOCAL","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"LOW","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"MEDIUM","baseScore":5.1,"vectorString":"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"}}],"credits":[{"lang":"en","value":"Michał Majchrowicz (AFINE Team)","type":"finder"},{"lang":"en","value":"Marcin Wyczechowski (AFINE Team)","type":"finder"}],"source":{"discovery":"EXTERNAL"},"x_generator":{"engine":"Vulnogram 0.2.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-02T12:16:34.432412Z","id":"CVE-2026-54431","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-07-02T12:16:41.569Z"}}]}}