> CVE-2026-28496 [CRITICAL]

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PUBLISHED
2026-06-23 15:16
MODIFIED
2026-06-23 15:44
CVSS_SCORE V3
9.4
EPSS (Prob. Exploit)
1.91%
Top 20.3%
🎯 NUCLEI TEMPLATE
DATA SOURCES:
NVD 🔗 2026-06-23 CWE MITRE 🔗 2026-11-01 FIRST EPSS 🔗 2026-11-01 OSV 🔗 2026-11-02 NUCLEI 🔗 2026-11-01

> 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.

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_VECTOR
CVSS:4.0/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

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:4.0/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
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
AC (Complexité d'Attaque)
Attack Complexity
Low (L)
Peu de conditions requises pour exploiter
PR (Privilèges Requis)
Privileges Required
High (H)
Authentifié avec privilèges administratifs
UI (Interaction Utilisateur)
User Interaction
None (N)
Aucune interaction utilisateur nécessaire
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
High (H)
Divulgation totale d'informations
I (Impact Intégrité)
Integrity Impact
High (H)
Modification totale des données possible
A (Impact Disponibilité)
Availability Impact
High (H)
Interruption totale du service possible

> RÉSUMÉ DES IMPACTS

Confidentialité
High
Divulgation totale d'informations
Intégrité
High
Modification totale des données possible
Disponibilité
High
Interruption totale du service possible

> WEAKNESSES

CWE-1336

> CWE DETAILED DESCRIPTIONS

CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine - The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when processed by the engine.

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

FOSSBilling: Server-side template injection in Twig template rendering enables information disclosure and RCE

AFFECTED PACKAGES:
Unknown / Unknown
50 versions affected

> NUCLEI TEMPLATES

Des templates Nuclei sont disponibles pour scanner cette vulnérabilité.

🎯
CVE-2026-28496.yaml
http/cves/2026/CVE-2026-28496.yaml
Usage: nuclei -t http/cves/2026/CVE-2026-28496.yaml -u target.com

> HISTORIQUE DES MODIFICATIONS

Première apparition
23/06/2026 15:16
Source: NVD
📊 ENRICHISSEMENT 01/07/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine - The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or inc...
Total des modifications: 1 Dernière mise à jour: 4 months ago

> REFERENCES

https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-57mv-jm88-66...
https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-78x5-c8gw-82...
https://www.vulncheck.com/blog/fossbilling-auth-bypass-ssti-rce
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