Vulnerability · Published Jul 6, 2026 · Assigned by GitHub_M
CVE-2026-53646FOSSBilling: Client password reset token reuse allows persistent account takeover
High 7.7
In plain English
A high-severity security flaw in FOSSBilling from FOSSBilling. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities).
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| FOSSBilling | FOSSBilling | >= 0.5.6, < 0.8.0 |
Weakness: CWE-640 · Vector: 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