CVE-2026-39924 HIGH

CVE-2026-39924: Flarum < 1.8.16 Session Persistence via Improper Access Token Revocation

Vendor Flarum
Product Flarum Framework
Weakness CWE-613 · Insufficient session expiration
Published August 5, 2026
Last update August 5, 2026

CVSS base score

7.6/10
Attack vector Network
Attack complexity High
Privileges required Low
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

August 5, 2026 CVE published