Lemonldap::NG up to 2.21.5/2.23.3 Token Introspection checkEndPointAuthenticationCredentials improper authentication

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Lemonldap::NG up to 2.21.5/2.23.3. The impacted element is the function checkEndPointAuthenticationCredentials of the component Token Introspection. The manipulation leads to improper authentication. This vulnerability is listed as CVE-2026-92288. The attack may be initiated remotely. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Lemonldap::NG up to 2.21.5/2.23.3. It has been rated as problematic. This issue affects the function checkEndPointAuthenticationCredentials of the component Token Introspection. The manipulation with an unknown input leads to a improper authentication vulnerability. Using CWE to declare the problem leads to CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. Impacted is confidentiality. The summary by CVE is:

Lemonldap::NG::Portal versions from 2.20.0 before 2.21.6, from 2.22.0 before 2.23.4 for Perl allow unauthenticated OAuth2 token introspection because checkEndPointAuthenticationCredentials does not verify the client secret of a public Relying Party. checkEndPointAuthenticationCredentials() skips the secret comparison for a Relying Party marked public and still returns the authentication method deduced from the request, client_secret_basic or client_secret_post. introspection() rejects a caller only when that method is missing or none, so a request carrying a public client_id and an arbitrary or empty secret passes the endpoint's authentication check. An attacker who holds an access token and knows the client_id of any public Relying Party can confirm the token is active and read its metadata, including scope, audience, expiry and the sub claim. The sub claim is computed with the calling Relying Party's user identifier attribute, so an attacker can translate a user identifier from one Relying Party to another, defeating per-client and pseudonymous identifiers.

It is possible to read the advisory at gitlab.ow2.org. The identification of this vulnerability is CVE-2026-92288 since 09/16/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 2.21.6 or 2.23.4 eliminates this vulnerability.

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Productinfo

Type

• Directory Service Software

Name

• Lemonldap::NG

Version

• 2.21.0
• 2.21.1
• 2.21.2
• 2.21.3
• 2.21.4
• 2.21.5
• 2.23.0
• 2.23.1
• 2.23.2
• 2.23.3

CPE 2.3info

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CPE 2.2info

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