CVE-2026-53641

CVE-2026-53641 is a medium-severity vulnerability with a CVSS 4.0 base score of 4.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

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.

Frequently asked questions

What is CVE-2026-53641?
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.
How severe is CVE-2026-53641?
CVE-2026-53641 has a CVSS 4.0 base score of 4.8, rated medium severity.
Is CVE-2026-53641 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-53641?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-53641 published?
CVE-2026-53641 was published on 2026-07-06 and last updated on 2026-07-07.

References

Other CWE-79 (Cross-site Scripting (XSS)) vulnerabilities

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