High Privilege escalation

CVE-2026-53645 — FOSSBilling's missing self-edit prevention in staff permission management allows persistent privilege escalation

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.

Published Jul 6, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: GitHub_M

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

FOSSBilling

CVSS base

8.5

High · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (FOSSBilling FOSSBilling).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes matching the vulnerability class (privilege escalation), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
FOSSBilling	FOSSBilling	version < 0.8.0	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Attack requirements

None

Privileges required

Low

User interaction

None

Scope

Confidentiality (vulnerable system)

None

Integrity (vulnerable system)

High

Availability (vulnerable system)

None

Confidentiality (subsequent)

High

Integrity (subsequent)

High

Availability (subsequent)

Low

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
8.5	CVSS 4.0	High	—	—	security-advisories@github.com via NIST National Vulnerability Database
8.5	CVSS 4.0	High	—	—	GitHub_M via CVE Program (cve.org) e CISA ADP

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

(score shown at the top: security-advisories@github.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-269 · Improper Privilege Management

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).

web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

2026
Affected products added · fossbilling/fossbilling
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 15, 2026
CVSS changed · 8.5
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Deferred
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Jul 6, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

1 on the record

github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-4hf7-xxxw-64rm
x_refsource_CONFIRM, NIST National Vulnerability Database

Elsewhere on this site

FOSSBilling
every CVE for this vendor

Privilege escalation
same class

CWE-269
other pages naming this weakness

Related CVEs (same products)

Medium CVE-2026-53648 FOSSBilling: Downloadable product files can be overwritten through filename collisions Jul 6, 2026
Medium CVE-2026-53647 FOSSBilling vulnerable to unauthenticated API key configuration disclosure via guest Serviceapikey get_info endpoint Jul 6, 2026
Medium CVE-2026-53642 FOSSBilling: Unverified clients can access client-area pages when email confirmation is required Jul 6, 2026
High CVE-2026-53643 FOSSBilling allows low-privileged staff accounts to perform unauthorized actions via admin API endpoints Jul 6, 2026
High CVE-2026-53646 FOSSBilling: Client password reset token reuse allows persistent account takeover Jul 6, 2026
High CVE-2026-53644 FOSSBilling's missing order-state validation allows clients to read and reset API key secrets for non-active orders Jul 6, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No FIRST EPSS score.
No fixed version, patch or mitigation documented.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-53645 is "FOSSBilling's missing self-edit prevention in staff permission management allows persistent privilege escalation", rated High. It affects FOSSBilling (FOSSBilling); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.5 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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