CVE & CISA-KEV Catalog

CVE-2026-39923

HIGH
8.1
CVSS v3
NVD

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.

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

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CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

0.26%probability of exploitation in 30 days
18thpercentile

Low risk: more likely to be exploited than 18% of all known CVEs.

References

Related Vulnerabilities

Other CWE-324 vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2022-35401High8.121%--
CVE-2024-36031Critical9.80.7%-Fix
CVE-2019-3790Medium6.10.7%-Fix
CVE-2022-2447Medium6.60.6%-Fix
CVE-2021-33020High8.20.6%-Fix
CVE-2022-24732Medium6.30.4%-Fix

Common questions

How do I fix CVE-2026-39923?

No published fix for CVE-2026-39923 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

Is CVE-2026-39923 being actively exploited?

Not that we know of. CVE-2026-39923 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.26% is the estimated probability that it will be exploited in the next 30 days. That is higher than 18% of all scored CVEs.

How severe is CVE-2026-39923?

CVE-2026-39923 has a CVSS v3 base score of 8.1, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-08-05.