CVE-2026-43918: high-severity vulnerability in FOSSBilling
Suspended or inactive FOSSBilling accounts can retain or regain access through existing sessions, API tokens, and password reset flows
Published · Updated
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.7epss 0.4%
FOSSBilling is a free, open-source billing and client management system. Prior to version 0.8.0, when a client or staff/admin account is suspended or marked inactive, existing authenticated sessions are not invalidated. The session identity loaders in src/di.php (loggedin_client and loggedin_admin) only reject sessions if the backing account record no longer exists in the database. They do not verify that the account's status is still active. This allows a suspended or deactivated user to retain full access until their session naturally expires. This issue has been fixed in version 0.8.0.
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Affected products
FOSSBilling · FOSSBillingRelated CVEs — FOSSBilling
In the same product, most dangerous first.
CVE-2026-28496CRITICALFOSSBilling: Server-side template injection in Twig template rendering enables information disclosure and RCEEPSS 1.9%CVE-2026-27604CRITICALFOSSBilling: Improper API Role Validation (system) Enables Unauthenticated Access to Privileged Admin FunctionsEPSS 1.3%CVE-2026-43920MEDIUMFOSSBilling: Unauthenticated update patcher endpoint allows remote maintenance executionEPSS 0.9%CVE-2026-53647MEDIUMFOSSBilling vulnerable to unauthenticated API key configuration disclosure via guest Serviceapikey get_info endpointEPSS 0.5%CVE-2026-43925MEDIUMFOSSBilling: Mass assignment of group_id in guest client registration allows unauthorized promo code useEPSS 0.5%CVE-2026-33543CRITICALFOSSBilling: Authentication bypass allows unauthenticated administrator creationEPSS 0.4%