# CVE-2026-53644 — FOSSBilling

> As of 2026-07-07, CVE-2026-53644 is a High-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in FOSSBilling, CVSS v4.0 8.6, EPSS 0.2% (16.3th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-53644 as of 2026-07-07; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-07-07

## What is CVE-2026-53644?

FOSSBilling is a free, open-source billing and client management system. Versions 0.5.3 through 0.7.2 allow authenticated clients to both read and reset API key service secrets for orders that are no longer in an `active` state (e.g., `suspended`, `canceled`). The root cause is missing order-state validation in two client API endpoints, despite an `isActive()` helper already existing in the `Serviceapikey` module and the frontend UI correctly gating access on `order.status == 'active'`. Version 0.8.0 contains a fix. Some workarounds are available. If the `Serviceapikey` module is not needed, uninstall it to remove the affected endpoints. One may also use a reverse proxy or WAF to restrict access to `/api/client/order/service` and `/api/client/serviceapikey/reset` based on application-level order-state logic.

The record classifies CVE-2026-53644 under weakness class [CWE-639](https://intel.threadlinqs.com/cwe/CWE-639). 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 91 days ago.

## Severity and exploitation probability

- **CVSS v4.0 base score:** 8.6 — High (derived from score) (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **EPSS (FIRST):** 0.2% probability of exploitation in the next 30 days, higher than 16.3% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 5/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-07-06, last modified 2026-07-07

## Is CVE-2026-53644 being exploited?

It currently carries a trending score of 34 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [FOSSBilling](https://intel.threadlinqs.com/vendors/fossbilling): FOSSBilling

## How to fix CVE-2026-53644

No vendor patch reference has been recorded for CVE-2026-53644 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-53644

No threat campaign in the Threadlinqs corpus currently references CVE-2026-53644, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, NVD, FIRST EPSS. Last verified by Threadlinqs on 2026-07-07. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [github.com](https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-qf6j-vq68-qmfh)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-53644
Full detection coverage and IOCs for threats exploiting CVE-2026-53644 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp