CVE-2026-39924 Flarum < 1.8.16 Session Persistence via Improper Access Token Revocation
Attackers retain account access after password changes because session tokens are not revoked, allowing persistent unauthorized access to user accounts.
- 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-2026-39924?
CVE-2026-39924 is a high-severity authentication bypass vulnerability in Flarum Framework, published on 5 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Flarum before 1.8.16 contains an improper session invalidation vulnerability that allows attackers who hold a valid session token to retain full account access after a victim changes their password, because the access_tokens table is never cleared on password change events. The TokensClearer::clearPasswordTokens() function only removes rows from the password_tokens table while leaving all active session cookies and API bearer tokens intact, including long-lived RememberAccessToken entries, and administrator-forced password resets via the user update endpoint are equally ineffective at revoking attacker-held sessions.
Weakness: CWE-613
Which versions are affected by CVE-2026-39924?
How do I fix CVE-2026-39924?
No fix has been published for CVE-2026-39924 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-2026-39924 being exploited?
There is no known exploitation of CVE-2026-39924 in the wild and no public exploit code.
Sources
Also known as GHSA-4x2h-wcjq-p974.