CVE-2026-43920
FOSSBilling: Unauthenticated update patcher endpoint allows remote maintenance execution
Description
FOSSBilling is a free, open-source billing and client management system. In versions 0.5.4 through 0.7.2, the /run-patcher maintenance endpoint in FOSSBilling was accessible without authentication, which allowed unauthenticated remote users to trigger update patch routines that modify configuration files, execute database schema changes, perform filesystem mutations, and clear caches. The /run-patcher endpoint executes privileged maintenance operations - configuration migrations, database patch execution (including ALTER TABLE, DROP TABLE, UPDATE statements), filesystem deletions and renames, and cache clearing - without requiring administrator authentication, CSRF validation, or CLI context. An unauthenticated remote attacker can trigger these operations by sending a simple HTTP GET request to /run-patcher, which can be abused for denial-of-service attacks. Certain patches (e.g., batch token regeneration for all admin and client accounts in patch 53, and session invalidation) are disruptive even when re-executed against an already-patched instance. Repeated or concurrent requests may also cause inconsistent database state. This issue has been fixed in version 0.8.0.
INFO
Published Date :
June 26, 2026, 12:16 a.m.
Last Modified :
June 26, 2026, 4:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update FOSSBilling to version 0.8.0.
- Restrict access to maintenance endpoints.
- Apply all available security patches promptly.
- Regularly review system configurations.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-43920.
| URL | Resource |
|---|---|
| https://github.com/FOSSBilling/FOSSBilling/releases/tag/0.8.0 | |
| https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-prx6-m547-rfmg |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-43920 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-43920
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-43920 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-43920 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 26, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-43920', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-26T13:40:02.131727Z'} -
New CVE Received by [email protected]
Jun. 26, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'FOSSBilling', 'product': 'FOSSBilling', 'versions': [{'status': 'affected', 'version': '>= 0.5.4, < 0.8.0'}]}] Added Description FOSSBilling is a free, open-source billing and client management system. In versions 0.5.4 through 0.7.2, the /run-patcher maintenance endpoint in FOSSBilling was accessible without authentication, which allowed unauthenticated remote users to trigger update patch routines that modify configuration files, execute database schema changes, perform filesystem mutations, and clear caches. The /run-patcher endpoint executes privileged maintenance operations - configuration migrations, database patch execution (including ALTER TABLE, DROP TABLE, UPDATE statements), filesystem deletions and renames, and cache clearing - without requiring administrator authentication, CSRF validation, or CLI context. An unauthenticated remote attacker can trigger these operations by sending a simple HTTP GET request to /run-patcher, which can be abused for denial-of-service attacks. Certain patches (e.g., batch token regeneration for all admin and client accounts in patch 53, and session invalidation) are disruptive even when re-executed against an already-patched instance. Repeated or concurrent requests may also cause inconsistent database state. This issue has been fixed in version 0.8.0. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-306 Added Reference https://github.com/FOSSBilling/FOSSBilling/releases/tag/0.8.0 Added Reference https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-prx6-m547-rfmg