# CVE-2026-53646: FOSSBilling: Client password reset token reuse allows persistent account takeover

> Attackers can reuse old password reset tokens to take over accounts because the system fails to invalidate previous tokens when new ones are requested.

- **Severity:** High 7.7 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 6 Jul 2026
- **Updated:** 7 Jul 2026
- **Also known as:** GHSA-vp66-w6rc-x32p

## What is CVE-2026-53646?

CVE-2026-53646 is a high-severity vulnerability in FOSSBilling, published on 6 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

FOSSBilling is a free, open-source billing and client management system. In versions 0.5.6 through 0.7.2, when a `ClientPasswordReset` record already exists for a client (from a previous unexpired reset request), subsequent calls to the `reset_password` guest API endpoint reuse the existing token instead of generating a new one. The 15-minute validity window is anchored to the first request's `created_at` timestamp, not the time of the most recent email. An attacker who obtained the original reset link remains able to use it even after the victim requests a new reset, because the original token is never invalidated or rotated. Version 0.8.0 patches the issue. Some workarounds are available. Configure a reverse proxy (e.g., Nginx, Apache, Cloudflare) to apply per-IP rate limiting to the `/client/reset-password` endpoint to minimize the window of opportunity, and/or manually clear expired `client_password_reset` records from the database after a client reports a suspected compromise.

Weakness: CWE-640 (Weak Password Recovery Mechanism for Forgotten Password)

## Which versions are affected by CVE-2026-53646?


## How do I fix CVE-2026-53646?

No fix has been published for CVE-2026-53646 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-53646 being exploited?

There is no known exploitation of CVE-2026-53646 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53646 and fix it if it is affected.

What it is: CVE-2026-53646 is a high-severity vulnerability in FOSSBilling, published on 6 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-53646 in the wild and no public exploit code.

Affected product: FOSSBilling. 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-2026-53646/ (Markdown: https://insights.sbomify.com/CVE-2026-53646/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53646
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53646
- OSV: https://osv.dev/vulnerability/CVE-2026-53646

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53646/
Summaries are generated and may contain mistakes; the official description above is the record.