# CVE-2026-85590: phpMyFAQ before 4.1.8 Authentication Bypass via Two-Factor Disable

> An attacker with a hijacked session can disable two-factor authentication, enabling password-only access to any account, including administrators.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/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:** 4 Sep 2026
- **Updated:** 4 Sep 2026
- **Also known as:** GHSA-h96g-59xp-7r5m, GHSA-x283-48fh-hc5w

## What is CVE-2026-85590?

CVE-2026-85590 is a high-severity authentication bypass vulnerability in thorsten phpMyFAQ, published on 4 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

phpMyFAQ before 4.1.8 contains an authentication bypass vulnerability in its two-factor authentication (TOTP) disable functionality. The removeTwofactorConfig() handler (reachable via POST /api/user/remove-twofactor) verifies only that the user is logged in and that a valid CSRF token is supplied, then disables TOTP without requiring password re-entry or a current TOTP code. The same downgrade is also reachable inline via PUT /api/user/data/update, which accepts a plain twofactor_enabled form field under the same session+CSRF-only guard. An attacker who has hijacked a user's session can silently strip two-factor protection from any account, including administrator accounts, after which password-only authentication succeeds.

Weakness: CWE-308 (Use of Single-factor Authentication)

## Which versions are affected by CVE-2026-85590?


## How do I fix CVE-2026-85590?

No fix has been published for CVE-2026-85590 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-85590 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-85590 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-85590 and fix it if it is affected.

What it is: CVE-2026-85590 is a high-severity authentication bypass vulnerability in thorsten phpMyFAQ, published on 4 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-85590 exists.

Affected product: thorsten phpMyFAQ. 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-2026-85590/ (Markdown: https://insights.sbomify.com/CVE-2026-85590/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-85590
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-85590
- OSV: https://osv.dev/vulnerability/CVE-2026-85590

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-85590/
Summaries are generated and may contain mistakes; the official description above is the record.