CVE-2026-39923 CRITICAL

CVE-2026-39923: Flarum < 1.8.16 Password Reset Token Expiry Bypass via POST /reset

Vendor Flarum
Product Flarum Framework
Weakness CWE-324
Published August 5, 2026
Last update August 5, 2026

CVSS base score

9.2/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

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

What the vulnerability does

01Description

Flarum before 1.8.16 contains a password reset token expiry bypass vulnerability that allows unauthenticated attackers to reuse expired password reset tokens by submitting them directly to the reset processing endpoint. The SavePasswordController::handle() method calls PasswordToken::findOrFail() without performing any expiry validation, allowing attackers to bypass the 24-hour token lifetime enforced only during form rendering and change any account's password to gain an authenticated session.

Key dates

02Disclosure timeline

August 5, 2026 CVE published