{"id":"CVE-2026-82462","state":"PUBLISHED","title":"pac4j-oidc before 6.5.6 Authentication Bypass via Access Token Substitution","description":"pac4j-oidc before 6.5.6 accepts OIDC callbacks carrying only an access token without authorization code or ID token validation. Attackers can substitute access tokens minted for other clients to create authenticated sessions without proper issuer, audience, nonce, or subject verification.","publishedAt":"2026-08-29T16:35:26.177Z","updatedAt":"2026-08-31T18:19:02.291Z","severity":{"score":6.9,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","source":"VulnCheck"},"assigner":"VulnCheck","products":["pac4j pac4j"],"affected":[{"vendor":"pac4j","product":"pac4j","packageURL":"pkg:maven/org.pac4j/pac4j-parent","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"6.5.6","versionType":"semver"}]}],"references":["https://github.com/pac4j/pac4j/commit/2270c3ff70e93cc43831e75702acd5135531237e","https://www.pac4j.org/blog/security-advisory-pac4j-core-oidc-saml.html","https://github.com/pac4j/pac4j/blob/pac4j-parent-6.5.5/pac4j-oidc/src/main/java/org/pac4j/oidc/credentials/extractor/OidcCredentialsExtractor.java","https://github.com/pac4j/pac4j","https://www.vulncheck.com/advisories/pac4j-oidc-before-6.5.6-authentication-bypass-via-access-token-substitution"],"weaknesses":["CWE-345"],"ingestedAt":"2026-10-29T20:13:15.269Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/82xxx/CVE-2026-82462.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-82462","state":"PUBLISHED","datePublished":"2026-08-29T16:35:26.177Z","dateUpdated":"2026-08-31T18:19:02.291Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-08-29T14:11:00.606Z"},"containers":{"cna":{"title":"pac4j-oidc before 6.5.6 Authentication Bypass via Access Token Substitution","descriptions":[{"lang":"en","value":"pac4j-oidc before 6.5.6 accepts OIDC callbacks carrying only an access token without authorization code or ID token validation. Attackers can substitute access tokens minted for other clients to create authenticated sessions without proper issuer, audience, nonce, or subject verification."}],"affected":[{"vendor":"pac4j","product":"pac4j","packageURL":"pkg:maven/org.pac4j/pac4j-parent","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"6.5.6","versionType":"semver"}]}],"references":[{"url":"https://github.com/pac4j/pac4j/commit/2270c3ff70e93cc43831e75702acd5135531237e","tags":["patch"],"name":"Patch Commit"},{"url":"https://www.pac4j.org/blog/security-advisory-pac4j-core-oidc-saml.html","tags":["vendor-advisory"],"name":"pac4j Security Advisory for pac4j-core, pac4j-oidc and pac4j-saml"},{"url":"https://github.com/pac4j/pac4j/blob/pac4j-parent-6.5.5/pac4j-oidc/src/main/java/org/pac4j/oidc/credentials/extractor/OidcCredentialsExtractor.java","tags":["technical-description"]},{"url":"https://github.com/pac4j/pac4j","tags":["product"]},{"url":"https://www.vulncheck.com/advisories/pac4j-oidc-before-6.5.6-authentication-bypass-via-access-token-substitution","name":"VulnCheck Advisory: pac4j-oidc before 6.5.6 Authentication Bypass via Access Token Substitution","tags":["third-party-advisory"]}],"metrics":[{"format":"CVSS","cvssV4_0":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.9,"baseSeverity":"MEDIUM"}},{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"LOW","availabilityImpact":"NONE","baseScore":6.5,"baseSeverity":"MEDIUM"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-345","lang":"en","description":"Insufficient Verification of Data Authenticity","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-08-29T16:35:26.177Z"},"datePublic":"2026-08-24T00:00:00.000Z","cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:pac4j:pac4j:*:*:*:*:*:*:*:*","versionEndExcluding":"6.5.6"}]}]}],"credits":[{"lang":"en","value":"Joshua Rogers (AISLE Research)","type":"finder"}],"x_generator":{"engine":"vulncheck-endgame"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-31T18:18:53.077600Z","id":"CVE-2026-82462","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-31T18:19:02.291Z"}}]}}}