What’s Vulnerable › Vulnerabilities
CVE-2026-53641: FOSSBilling has stored XSS in client email views via unescaped content in JavaScript template literal
- Severity: medium (CVSS 4.8 v4.0)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.4% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-07-06 · updated 2026-07-08
- Weakness: CWE-79
Description
FOSSBilling is a free, open-source billing and client management system. Versions 0.6.0 through 0.7.2 have a stored cross-site scripting (XSS) vulnerability in the client-facing email history views of FOSSBilling. Email HTML content (`content_html`) is rendered into a JavaScript template literal using the `|raw` filter, bypassing all output escaping. An attacker with admin access can inject malicious JavaScript payloads into email content that execute in the browser of any client who views their email history. Version 0.8.0 contains a fix. Some workarounds are available. Restrict admin account access, audit email content in the database for suspicious payloads, and/or monitor client accounts for unusual activity.
Affected products
- FOSSBilling: from 0.6.0, < 0.8.0
References
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