CVE-2026-67351 Serendipity < 2.6.1 Authentication Bypass via Username Collision
An authenticated Editor can escalate privileges to Administrator by exploiting a username collision vulnerability in Serendipity.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-67351?
CVE-2026-67351 is a high-severity authentication bypass vulnerability in s9y Serendipity, published on 30 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Serendipity before 2.6.1 contains an authentication context confusion vulnerability where password validation and session loading operate independently without ensuring both use the same user record. An authenticated Editor can create a username collision with an Administrator account and obtain administrative privileges by logging in with their own password while the session loads the Administrator's account data.
Weakness: CWE-304
Which versions are affected by CVE-2026-67351?
How do I fix CVE-2026-67351?
No fix has been published for CVE-2026-67351 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-67351 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-67351 exists.
Sources
Also known as GHSA-v645-243f-jwgh.