CVE-2026-28496
FOSSBilling: Server-side template injection in Twig template rendering enables information disclosure and RCE
Description
FOSSBilling is a free, open-source billing and client management system. Versions prior to 0.8.0 have a Server-Side Template Injection (SSTI) vulnerability in the template rendering system. Administrators with access to features that render Twig templates (email templates, mass mail campaigns, custom payment adapters, and the `string_render` API endpoint) can inject arbitrary Twig expressions, leading to information disclosure and remote code execution. The vulnerability exists because Twig templates are rendered without a sandbox, allowing access to the full Twig environment, API context, and the application's dependency injection container. Version 0.8.0 patches the issue. Some workarounds are available. Audit existing email templates for suspicious Twig expressions, rotate all admin and client API tokens, and/or block external access to /api/system/* at reverse proxy/WAF to mitigate chaining with GHSA-78x5-c8gw-8279.
INFO
Published Date :
June 23, 2026, 3:16 p.m.
Last Modified :
June 23, 2026, 4:16 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 | CRITICAL | [email protected] |
Solution
- Update FOSSBilling to version 0.8.0 or later.
- Audit email templates for suspicious Twig expressions.
- Rotate all admin and client API tokens.
- Block external access to /api/system/*.
Public PoC/Exploit Available at Github
CVE-2026-28496 has a 4 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
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-2026-28496.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-28496 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-2026-28496
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).
None
Dockerfile Python Shell
备份的漏洞库，3月开始我们来维护
None
📡 PoC auto collect from GitHub. ⚠️ Be careful Malware.
security cve exploit poc vulnerability
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-28496 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-28496 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. 23, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-28496', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-06-23T15:02:54.282718Z'} -
New CVE Received by [email protected]
Jun. 23, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'FOSSBilling', 'product': 'FOSSBilling', 'versions': [{'status': 'affected', 'version': '< 0.8.0'}]}] Added Description FOSSBilling is a free, open-source billing and client management system. Versions prior to 0.8.0 have a Server-Side Template Injection (SSTI) vulnerability in the template rendering system. Administrators with access to features that render Twig templates (email templates, mass mail campaigns, custom payment adapters, and the `string_render` API endpoint) can inject arbitrary Twig expressions, leading to information disclosure and remote code execution. The vulnerability exists because Twig templates are rendered without a sandbox, allowing access to the full Twig environment, API context, and the application's dependency injection container. Version 0.8.0 patches the issue. Some workarounds are available. Audit existing email templates for suspicious Twig expressions, rotate all admin and client API tokens, and/or block external access to /api/system/* at reverse proxy/WAF to mitigate chaining with GHSA-78x5-c8gw-8279. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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-1336 Added Reference https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-57mv-jm88-66jc Added Reference https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-78x5-c8gw-8279 Added Reference https://www.vulncheck.com/blog/fossbilling-auth-bypass-ssti-rce