{"id":"CVE-2026-92289","title":"Lemonldap::NG::Portal versions from 2.23.0 before 2.23.4 for Perl allow a PKCE bypass for public Relying Parties in \"PKCE or secret\" mode because checkEndPointAuthenticationCredentials does not verify the client secret.\n\nWith oidcRPMetaD…","summary":"Lemonldap::NG::Portal versions from 2.23.0 before 2.23.4 for Perl allow a PKCE bypass for public Relying Parties in \"PKCE or secret\" mode because checkEndPointAuthenticationCredentials does not verify the client secret.\n\nWith oidcRPMetaD…","severity":"critical","cvss":9.1,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","cwe":["CWE-1390"],"vendor":"Red Hat","product":"Lemonldap-NG-Portal","affected":["Lemonldap-NG-Portal >= 2.23.0 < 2.23.4"],"published":"2026-09-25","updated":"2026-09-26","sourceUpdated":"2026-09-26T23:16:38.897","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-92289","references":[{"url":"https://gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/releases/v2.23.4","label":"9b29abf9-4ab0-4765-b253-1875cd9b441e"},{"url":"https://gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/work_items/3719","label":"9b29abf9-4ab0-4765-b253-1875cd9b441e"},{"url":"http://www.openwall.com/lists/oss-security/2026/09/25/2","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/work_items/3719","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-92289.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-92289"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-92289"}],"tags":["nvd","cve.org","exploit-available","csaf","vex","red-hat","score-dispute"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"yes","technicalImpact":"total","timestamp":"2026-09-25T15:38:54.575555Z"},"epss":0.00537,"epssPercentile":0.45064,"scores":{"nvd":9.1,"vendor":6.8,"adp":9.1},"ingestedAt":"2026-09-25T00:56:54.274Z","slug":"CVE-2026-92289","body":"## Overview\n\nLemonldap::NG::Portal versions from 2.23.0 before 2.23.4 for Perl allow a PKCE bypass for public Relying Parties in \"PKCE or secret\" mode because checkEndPointAuthenticationCredentials does not verify the client secret.\n\nWith oidcRPMetaDataOptionsRequirePKCE set to 2, the authorization endpoint issues a code even when the request carries no code_challenge, and token() admits the exchange as long as a challenge was stored or an authentication method was returned for the caller. checkEndPointAuthenticationCredentials() skips the secret comparison for a Relying Party marked public and still returns the method deduced from the request, so any Basic or form credential satisfies the secret branch. validatePKCEChallenge() then passes, because neither a challenge nor a verifier is present.\n\nAn attacker who intercepts an authorization code issued to a public Relying Party can exchange it for the user's access, ID and refresh tokens by replaying the client_id with an arbitrary secret, which is the attack PKCE prevents. Dynamic client registration creates every Relying Party in this mode.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · updated 2026-09-25 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-92289.json)","depth":"abyssal","depthScore":62,"depthScoreParts":{"impact":50.1,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":211465,"id":"CVE-2026-92289","ts":1790466009522,"field":"cvss","old":"6.8","new":"9.1"},{"seq":211464,"id":"CVE-2026-92289","ts":1790466009522,"field":"severity","old":"medium","new":"critical"},{"seq":211042,"id":"CVE-2026-92289","ts":1790352783719,"field":"exploit_available","old":"false","new":"true"},{"seq":210651,"id":"CVE-2026-92289","ts":1790322139341,"field":"cvss","old":null,"new":"6.8"},{"seq":210650,"id":"CVE-2026-92289","ts":1790322139341,"field":"severity","old":"none","new":"medium"}]}