# CVE-2026-92289: lemonldap-ng: Lemonldap::NG::Portal versions from 2.23.0 before 2.23.4 for Perl allow a PKCE bypass for public Relying Parties in "...

CVE-2026-92289 is fixed in 11 products on 1 platform, first by FEDORA-2026-33DCAB55B4, released September 25, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2026-92289
- Priority: Urgent
- CVSS: 9.1 (critical)
- EPSS: 0.0054
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 25, 2026

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | lemonldap-ng Debian 13.5 (trixie) | 2.21.2+ds-1+deb13u4 | [DEBIAN-CVE-2026-92289](https://patchblox.com/security/data/fix/linux/debian-cve-2026-92289.md) | Sep 27, 2026 |
| Linux | lemonldap-ng Debian 14 | 2.23.4+ds-1 | [DEBIAN-CVE-2026-92289](https://patchblox.com/security/data/fix/linux/debian-cve-2026-92289.md) | Sep 27, 2026 |
| Linux | lemonldap-ng Fedora 43 | 2.23.4-1.fc43 | [FEDORA-2026-33DCAB55B4](https://patchblox.com/security/data/fix/linux/fedora-2026-33dcab55b4.md) | Sep 25, 2026 |
| Linux | lemonldap-ng-common Fedora 43 | 2.23.4-1.fc43 | [FEDORA-2026-33DCAB55B4](https://patchblox.com/security/data/fix/linux/fedora-2026-33dcab55b4.md) | Sep 25, 2026 |
| Linux | lemonldap-ng-doc Fedora 43 | 2.23.4-1.fc43 | [FEDORA-2026-33DCAB55B4](https://patchblox.com/security/data/fix/linux/fedora-2026-33dcab55b4.md) | Sep 25, 2026 |
| Linux | lemonldap-ng-fastcgi-server Fedora 43 | 2.23.4-1.fc43 | [FEDORA-2026-33DCAB55B4](https://patchblox.com/security/data/fix/linux/fedora-2026-33dcab55b4.md) | Sep 25, 2026 |
| Linux | lemonldap-ng-handler Fedora 43 | 2.23.4-1.fc43 | [FEDORA-2026-33DCAB55B4](https://patchblox.com/security/data/fix/linux/fedora-2026-33dcab55b4.md) | Sep 25, 2026 |
| Linux | lemonldap-ng-manager Fedora 43 | 2.23.4-1.fc43 | [FEDORA-2026-33DCAB55B4](https://patchblox.com/security/data/fix/linux/fedora-2026-33dcab55b4.md) | Sep 25, 2026 |
| Linux | lemonldap-ng-portal Fedora 43 | 2.23.4-1.fc43 | [FEDORA-2026-33DCAB55B4](https://patchblox.com/security/data/fix/linux/fedora-2026-33dcab55b4.md) | Sep 25, 2026 |
| Linux | lemonldap-ng-selinux Fedora 43 | 2.23.4-1.fc43 | [FEDORA-2026-33DCAB55B4](https://patchblox.com/security/data/fix/linux/fedora-2026-33dcab55b4.md) | Sep 25, 2026 |
| Linux | lemonldap-ng-test Fedora 43 | 2.23.4-1.fc43 | [FEDORA-2026-33DCAB55B4](https://patchblox.com/security/data/fix/linux/fedora-2026-33dcab55b4.md) | Sep 25, 2026 |
| Linux | lemonldap-ng-uwsgi-app Fedora 43 | 2.23.4-1.fc43 | [FEDORA-2026-33DCAB55B4](https://patchblox.com/security/data/fix/linux/fedora-2026-33dcab55b4.md) | Sep 25, 2026 |
| Linux | perl-Lemonldap-NG-SSOaaS-Apache-Client Fedora 43 | 2.23.4-1.fc43 | [FEDORA-2026-33DCAB55B4](https://patchblox.com/security/data/fix/linux/fedora-2026-33dcab55b4.md) | Sep 25, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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