CVE-2026-53641: medium-severity vulnerability in FOSSBilling
FOSSBilling has stored XSS in client email views via unescaped content in JavaScript template literal
Published · Updated
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 4.8epss 0.4%
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.
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
Affected products
FOSSBilling · FOSSBillingRelated CVEs — FOSSBilling
In the same product, most dangerous first.
CVE-2026-28496CRITICALFOSSBilling: Server-side template injection in Twig template rendering enables information disclosure and RCEEPSS 1.9%CVE-2026-27604CRITICALFOSSBilling: Improper API Role Validation (system) Enables Unauthenticated Access to Privileged Admin FunctionsEPSS 1.3%CVE-2026-43920MEDIUMFOSSBilling: Unauthenticated update patcher endpoint allows remote maintenance executionEPSS 0.9%CVE-2026-53647MEDIUMFOSSBilling vulnerable to unauthenticated API key configuration disclosure via guest Serviceapikey get_info endpointEPSS 0.5%CVE-2026-43925MEDIUMFOSSBilling: Mass assignment of group_id in guest client registration allows unauthorized promo code useEPSS 0.5%CVE-2026-33543CRITICALFOSSBilling: Authentication bypass allows unauthenticated administrator creationEPSS 0.4%