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VulnerabilityCVE-2026-53645Published 2026-07-06

CVE-2026-53645 — FOSSBilling

high (derived)

As of 2026-07-07, CVE-2026-53645 is a High-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in FOSSBilling, CVSS v4.0 8.5, EPSS 0.2% (15.0th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-53645 as of 2026-07-07; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

CVSS v4.0
8.5/10High (derived)
EPSS
0.2%Higher than 15.0% of scored CVEs
CISA KEV
NoNot in the KEV catalog
Tracked threats
0None linked yet
Priority
4.9/10Threadlinqs triage score
Published
Updated 2026-07-07
CVSS v4.0 8.5 (High, derived from score) · EPSS 0.2% (higher than 15.0% of all scored CVEs) · Priority 4.9/10 · Published 2026-07-06

Last updated:

What is CVE-2026-53645?

FOSSBilling is a free, open-source billing and client management system. Versions prior to 0.8.0 allow a low-privileged staff account to grant arbitrary module permissions to itself through the admin API, resulting in persistent privilege escalation. A staff user that only has `staff.create_and_edit_staff` can call `/api/admin/staff/permissions_update` targeting their own account and write any permission structure, bypassing the intended role-based access control boundary. Version 0.8.0 patches the issue. Some workarounds are available. Restrict the `staff.create_and_edit_staff` permission to only highly trusted staff members and/or use a reverse proxy or WAF to restrict access to `/api/admin/staff/permissions_update` to specific trusted roles.

The record classifies CVE-2026-53645 under weakness class CWE-269. 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
8.5 — High (derived from score)
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:L
EPSS (FIRST)
0.2% probability of exploitation in the next 30 days, higher than 15.0% of all scored CVEs
CISA KEV
Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority
4.9/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published
2026-07-06, last modified 2026-07-07

Is CVE-2026-53645 being exploited?

It currently carries a trending score of 34 in the Threadlinqs vulnerability feed.

Affected products and versions

How to fix CVE-2026-53645

No vendor patch reference has been recorded for CVE-2026-53645 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-2026-53645

No threat campaign in the Threadlinqs corpus currently references CVE-2026-53645, 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