PHPNuxBill through 2025.3.20 contains an account takeover vulnerability in the customer password reset flow in system/controllers/forgot.php that allows unauthenticated attackers to brute-force the 6-digit otp_code. Attackers knowing a customer username can guess the code without attempt limits or lockout, then read the newly set password from the HTTP response to hijack the account.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
References 5
https://github.com/hotspotbilling/phpnuxbill
disclosure@vulncheck.com
https://github.com/hotspotbilling/phpnuxbill/blob/2025.3.13/system/controllers/…
disclosure@vulncheck.com
https://github.com/hotspotbilling/phpnuxbill/commit/c3c2a92d468af91136d747b7514…
disclosure@vulncheck.com
https://github.com/hotspotbilling/phpnuxbill/security/advisories/GHSA-337r-rrrc…
disclosure@vulncheck.com
https://www.vulncheck.com/advisories/phpnuxbill-through-2025.3.20-account-takeo…
disclosure@vulncheck.com