GHSA-rqwm-9m4j-f7g3HighCVSS 7.5

XenForo before 2.3.13 contains a signature verification logic error in the PayPal REST webhook...

Published
September 8, 2026
Last Modified
September 9, 2026

🔗 CVE IDs covered (1)

📋 Description

XenForo before 2.3.13 contains a signature verification logic error in the PayPal REST webhook handler that allows unauthenticated attackers to bypass payment signature validation by submitting a webhook request with an unsupported auth_algo header value. When the algorithm cannot be mapped to a supported hash function, the verification function incorrectly returns true instead of failing, causing the caller to treat the fabricated request as verified and process the payment event without a valid PayPal signature.

🔗 References (7)