CriticalFix available

lemonldap-ng — security advisory

Type: advisorySources: OSVAdvisory ID: DEBIAN-CVE-2026-92289

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.

Products: lemonldap-ng
Affected versions: 2.21.2+ds-1, 2.21.2+ds-1+deb13u1, 2.21.2+ds-1+deb13u2, 2.21.2+ds-1+deb13u3, 2.21.2+ds-2, 2.21.3+ds-1, 2.21.3+ds-1~bpo12+1, 2.21.3+ds-1~bpo13+1, 2.22.0+ds-1, 2.22.0+ds-2, 2.22.0+ds-2~bpo13+1, 2.22.1+ds-1, 2.22.1+ds-1~bpo13+1, 2.22.2+ds-1, 2.22.2+ds-1~bpo13+1, 2.22.3+ds-1, 2.22.3+ds-1~bpo13+1, 2.23.0+ds-1, 2.23.0+ds-2, 2.23.0+ds-3, 2.23.0+ds-3~bpo13+1, 2.23.0+ds-4, 2.23.1+ds-1, 2.23.2+ds-1, 2.23.2+ds-1~bpo13+1, 2.23.2+ds-2, 2.23.3+ds-1
Fixed versions: 2.21.2+ds-1+deb13u4, 2.23.4+ds-1
CVEs: CVE-2026-92289
Confirmed fixed CVEs: Not specified
Updated in this feed: 31 Oct 2026, 05:16 UTC · Revision 1

Source evidence

DEBIAN-CVE-2026-92289

core-osv · Original source

Published 25 Sept 2026, 01:16 UTC

osv:DEBIAN-CVE-2026-92289

lemonldap-ng

Fixed versions: 2.21.2+ds-1+deb13u4

lemonldap-ng

Fixed versions: 2.23.4+ds-1

Complete source record

{
  "id": "0e5d24c3f62c22dd6e8409f0182428dccffc96ac9085cb76aa2213c9768af2a0",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-92289",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2026-92289",
    "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.",
    "evidence": "osv:DEBIAN-CVE-2026-92289",
    "products": [
      {
        "name": {
          "value": "lemonldap-ng",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.21.2+ds-1+deb13u4",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "2.21.2+ds-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.21.2+ds-1+deb13u1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.21.2+ds-1+deb13u2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.21.2+ds-1+deb13u3",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "lemonldap-ng",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.23.4+ds-1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "2.21.2+ds-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.21.2+ds-2",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.21.3+ds-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.21.3+ds-1~bpo12+1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.21.3+ds-1~bpo13+1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.22.0+ds-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.22.0+ds-2",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.22.0+ds-2~bpo13+1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.22.1+ds-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.22.1+ds-1~bpo13+1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.22.2+ds-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.22.2+ds-1~bpo13+1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.22.3+ds-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.22.3+ds-1~bpo13+1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.23.0+ds-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.23.0+ds-2",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.23.0+ds-3",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.23.0+ds-3~bpo13+1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.23.0+ds-4",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.23.1+ds-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.23.2+ds-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.23.2+ds-1~bpo13+1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.23.2+ds-2",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.23.3+ds-1",
            "evidence": "/affected/1/versions"
          }
        ]
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "DEBIAN-CVE-2026-92289",
      "aliases": [
        "DEBIAN-CVE-2026-92289"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2.21.2+ds-1+deb13u4"
                }
              ]
            }
          ],
          "package": {
            "name": "lemonldap-ng",
            "purl": "pkg:deb/debian/lemonldap-ng?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "versions": [
            "2.21.2+ds-1",
            "2.21.2+ds-1+deb13u1",
            "2.21.2+ds-1+deb13u2",
            "2.21.2+ds-1+deb13u3"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-92289.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2.23.4+ds-1"
                }
              ]
            }
          ],
          "package": {
            "name": "lemonldap-ng",
            "purl": "pkg:deb/debian/lemonldap-ng?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "versions": [
            "2.21.2+ds-1",
            "2.21.2+ds-2",
            "2.21.3+ds-1",
            "2.21.3+ds-1~bpo12+1",
            "2.21.3+ds-1~bpo13+1",
            "2.22.0+ds-1",
            "2.22.0+ds-2",
            "2.22.0+ds-2~bpo13+1",
            "2.22.1+ds-1",
            "2.22.1+ds-1~bpo13+1",
            "2.22.2+ds-1",
            "2.22.2+ds-1~bpo13+1",
            "2.22.3+ds-1",
            "2.22.3+ds-1~bpo13+1",
            "2.23.0+ds-1",
            "2.23.0+ds-2",
            "2.23.0+ds-3",
            "2.23.0+ds-3~bpo13+1",
            "2.23.0+ds-4",
            "2.23.1+ds-1",
            "2.23.2+ds-1",
            "2.23.2+ds-1~bpo13+1",
            "2.23.2+ds-2",
            "2.23.3+ds-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-92289.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-18T04:00:09.027978174Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-92289"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2026-92289"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-92289",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 366690,
  "published_at": "2026-09-25T01:16:48.943+00:00"
}