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VulnerabilityCVE-2026-53641Published 2026-07-06

CVE-2026-53641 — FOSSBilling

medium (derived)

As of 2026-07-06, CVE-2026-53641 is a Medium-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in FOSSBilling, CVSS v4.0 4.8, EPSS 0.2% (20.4th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-53641 as of 2026-07-06; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

CVSS v4.0
4.8/10Medium (derived)
EPSS
0.2%Higher than 20.4% of scored CVEs
CISA KEV
NoNot in the KEV catalog
Tracked threats
0None linked yet
Priority
3.2/10Threadlinqs triage score
Published
CVSS v4.0 4.8 (Medium, derived from score) · EPSS 0.2% (higher than 20.4% of all scored CVEs) · Priority 3.2/10 · Published 2026-07-06

Last updated:

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.

The record classifies CVE-2026-53641 under weakness classes CWE-79, CWE-838. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 91 days ago.

Severity and exploitation probability

CVSS v4.0 base score
4.8 — Medium (derived from score)
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
EPSS (FIRST)
0.2% probability of exploitation in the next 30 days, higher than 20.4% of all scored CVEs
CISA KEV
Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority
3.2/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published
2026-07-06

Is CVE-2026-53641 being exploited?

It currently carries a trending score of 35 in the Threadlinqs vulnerability feed.

Affected products and versions

How to fix CVE-2026-53641

No vendor patch reference has been recorded for CVE-2026-53641 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

Threat activity tracking CVE-2026-53641

No threat campaign in the Threadlinqs corpus currently references CVE-2026-53641, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

Sources

Enriched from CVE.org, NVD, FIRST EPSS. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.

Vendor advisory and patch