CVE-2026-19349 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
Attackers can bypass authentication in LemonLDAP::NG Portal by replaying OAuth2 state parameters as SSO session cookies, gaining unauthorized access.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-19349?
CVE-2026-19349 is a critical authentication bypass vulnerability, published on 16 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-19349?
How do I fix CVE-2026-19349?
Upgrade to a fixed version.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-19349 being exploited?
There is no known exploitation of CVE-2026-19349 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-19349, GHSA-4vx7-c7qw-2vx4, UBUNTU-CVE-2026-19349.