# 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.

- **Severity:** High 7.6 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 5 Aug 2026
- **Updated:** 14 Aug 2026
- **Also known as:** GHSA-4x2h-wcjq-p974

## 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 (DEPRECATED: Insufficient Session Expiration)

## 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.

## Is CVE-2026-39924 being exploited?

There is no known exploitation of CVE-2026-39924 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-39924 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-39924 in the wild and no public exploit code.

Affected product: Flarum Framework. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-39924/ (Markdown: https://insights.sbomify.com/CVE-2026-39924/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-39924
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-39924
- OSV: https://osv.dev/vulnerability/CVE-2026-39924

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-39924/
Summaries are generated and may contain mistakes; the official description above is the record.