CVE-2026-92289 (GCVE-0-2026-92289)

Vulnerability from cvelistv5 – Published: 2026-09-25 00:15 – Updated: 2026-09-25 02:10
VLAI
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
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. With 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. An 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.
Severity
No CVSS data available.
CWE
Assigner
References
Impacted products
Vendor Product Version CPE status
Affected: 2.23.0 , < 2.23.4 (custom)
Show details on NVD website
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          "value": "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 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\u0027s 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."
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          "url": "https://gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/work_items/3719"
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          "url": "https://gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/releases/v2.23.4"
        }
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      "solutions": [
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          "lang": "en",
          "value": "Upgrade to Lemonldap-NG-Portal 2.23.4 or later."
        }
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      "source": {
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      "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",
      "workarounds": [
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          "value": "For deployments that cannot upgrade to 2.23.4, set RequirePKCE to 1 on public Relying Parties so that a code challenge is always required. Relying Parties created through dynamic registration are always in \"PKCE or secret\" mode, so that endpoint has to be disabled as well."
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    "datePublished": "2026-09-25T00:15:49.826Z",
    "dateReserved": "2026-09-15T23:43:48.309Z",
    "dateUpdated": "2026-09-25T02:10:01.838Z",
    "state": "PUBLISHED"
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          }
        ],
        "id": "CVE-2026-92289",
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        "metrics": {},
        "published": "2026-09-25T01:16:48.943",
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