CVE-2026-19349: lemonldap-ng (Perl module) · Authentication Bypass by Primary Weakness
Affects lemonldap-ng (Perl module)Source CVE Database V5
Not known to be exploited · CVSS 9.8 Critical.
Data as of 13 Nov 2026, 23:53 UTC
- EPSS
- 0.8% chance of exploitation in 30 days – higher than 57% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 16 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 14 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
GitHublemonldap-ng/lemonldap-ngpkg:github/lemonldap-ng/lemonldap-ngOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Until a fix is available, deployments should review their access control rules to ensure they do not rely on the default "default => accept" setting and instead enforce user identity and authentication level checks. Additionally, consider disabling the GitHub and LinkedIn authentication modules if not required. Monitor vendor communications for official patches or updates addressing this vulnerability.
Description
CVE-2026-19349 is a critical authentication bypass vulnerability in Lemonldap::NG::Portal affecting certain versions that use the GitHub and LinkedIn OAuth2 backends. The flaw allows an unauthenticated visitor to replay a session identifier used as an OAuth2 state parameter to gain a valid SSO session without proper authentication. This occurs because the state parameter is stored as a regular SSO session lacking user and authentication level attributes, which some default configurations accept. Only deployments with the GitHub or LinkedIn authentication modules enabled are affected.
References
- gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/releases/v2.23.3 (opens in a new tab)
- gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/releases/v2.21.5 (opens in a new tab)
- gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/releases/v2.16.9 (opens in a new tab)
- openwall.com/lists/oss-security/2026/08/16/2 (opens in a new tab)