CVE-2026-39923
CVE-2026-39923 is a high-severity vulnerability with a CVSS 3.x base score of 8.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-324.
Key facts
- Severity: High (CVSS 3.x base score 8.1)
- CVSS v4: 9.2
- EPSS exploit prediction: 0% (18th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-324
- Published:
- Last modified:
Description
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.
Frequently asked questions
- What is CVE-2026-39923?
- 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.
- How severe is CVE-2026-39923?
- CVE-2026-39923 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2026-39923 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-39923?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2026-39923 published?
- CVE-2026-39923 was published on 2026-08-05.
References
- https://github.com/flarum/framework/commit/2803058d0f9dc38252326070b46d4484fe5a857d
- https://github.com/flarum/framework/pull/4545
- https://github.com/flarum/framework/releases/tag/v1.8.16
- https://www.vulncheck.com/advisories/flarum-password-reset-token-expiry-bypass-via-post-reset
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- CVE-2026-52809 — Medium (CVSS 6.8): Gogs is an open source self-hosted Git service. Prior to 0.14.3, password-reset tokens are generated using…
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