Medium severity · published Jul 6, 2026
CVE-2026-53642
FOSSBilling: Unverified clients can access client-area pages when email confirmation is required
5.3
CVSS
0.4%
EPSS
No
On KEV
Description
FOSSBilling is a free, open-source billing and client management system. In versions 0.5.6 through 0.7.2, when the "Require Email Confirmation" setting is enabled, a logged-in client with an unverified email address (`email_approved = 0`) can access all client-area pages (e.g. `/client/balance`, `/client/order/list`, `/client/invoice`) and read real account data, including wallet balances and transaction history. The API-side enforcement correctly restricts unverified clients to only profile-related endpoints, but the page-side enforcement is overly permissive, allowing any request whose path starts with `/client`. Version 0.8.0 contains a fix. No known workarounds that don't involve modifying the source code are available.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 29% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FO
FOSSBilling · FOSSBilling
>= 0.5.6, < 0.8.0 · source: vendor
Affected product
FO
FOSSBilling
FOSSBilling
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