CVE-2026-27604

CRITICAL EPSS 32.6%
Published Jun 23, 20266d ago · Modified Jun 23, 20266d ago
10.0 CVSS 4.0
Critical
Find Similar
Published Jun 23, 2026 6d ago
Last Modified Jun 23, 2026 6d ago

Description

FOSSBilling is a free, open-source billing and client management system. Starting in version 0.5.4 and prior to version 0.8.0, an authorization bypass in the API role handling allows unauthenticated access to privileged `/api/system/*` endpoints. Because `system` resolves to the cron admin identity, attackers can invoke admin API methods without valid credentials, session, or CSRF token. Version 0.8.0 patches the issue. Some workarounds are available. Block external access to `/api/system/*` at reverse proxy/WAF, restrict API access by trusted source IPs only (`api.allowed_ips`), rotate all admin/client API tokens immediately, invalidate active sessions and reset high-privilege credentials, and/or review API request logs for suspicious `/api/system/` access and treat as potential incident.

CVSS Details

Base Score
10.0
Exploitability
—
Impact
—
Vector string
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
32.6% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 4

CWE-200 Exposure of Sensitive Information to an Unauthorized Actor Information Exposure
CWE-306 Missing Authentication for Critical Function Authentication
CWE-862 Missing Authorization Authorization
CWE-863 Incorrect Authorization Authorization

References 3

  • github.com https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-57mv-jm88-66jc
  • github.com https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-78x5-c8gw-8279
  • vulncheck.com https://www.vulncheck.com/blog/fossbilling-auth-bypass-ssti-rce

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.