OW2 LemonLDAP::NG up to 2.16.8/2.21.4/2.23.2 OAuth2 extractFormInfo state improper authentication

Summaryinfo

A vulnerability marked as critical has been reported in OW2 LemonLDAP::NG up to 2.16.8/2.21.4/2.23.2. This vulnerability affects the function extractFormInfo of the component OAuth2. Performing a manipulation of the argument state results in improper authentication. This vulnerability is known as CVE-2026-19349. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability classified as critical has been found in OW2 LemonLDAP::NG up to 2.16.8/2.21.4/2.23.2. This affects the function extractFormInfo of the component OAuth2. The manipulation of the argument state with an unknown input leads to a improper authentication vulnerability. CWE is classifying the issue as CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Lemonldap::NG::Portal versions from 2.0.0 before 2.16.9, from 2.17.0 before 2.21.5, from 2.22.0 before 2.23.3 for Perl allow authentication bypass via an OAuth2 state parameter stored as an SSO session in the GitHub and LinkedIn backends. Before redirecting to the identity provider, extractFormInfo() creates the state session with the positional call `getApacheSession( undef, 1, 0, 'GitHubState' )`. getApacheSession() takes a session id followed by a named argument hash, so the trailing arguments become that hash, `kind` defaults to SSO, and the state is written to the global session storage as a regular SSO session. Its identifier is handed to the unauthenticated visitor as the state parameter of the redirection URL. Any visitor who reaches the GitHub or LinkedIn endpoint can replay that identifier as a session cookie and obtain a valid SSO session without authenticating. The session holds neither _user nor authenticationLevel, which the shipped bootstrap configuration accepts because it grants virtual hosts a "default => accept" access rule; deployments whose rules test the user or require an authentication level are less exposed. Only configurations with the GitHub or LinkedIn authentication module enabled are affected.

The advisory is shared at gitlab.ow2.org. This vulnerability is uniquely identified as CVE-2026-19349 since 08/08/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available.

Upgrading to version 2.16.9, 2.21.5 or 2.23.3 eliminates this vulnerability.

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Productinfo

Type

• Directory Service Software

Vendor

• OW2

Name

• LemonLDAP::NG

Version

• 2.16.0
• 2.16.1
• 2.16.2
• 2.16.3
• 2.16.4
• 2.16.5
• 2.16.6
• 2.16.7
• 2.16.8
• 2.21.0
• 2.21.1
• 2.21.2
• 2.21.3
• 2.21.4
• 2.23.0
• 2.23.1
• 2.23.2

CPE 2.3info

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CPE 2.2info

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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