HIGH 8.7 NVD
CVE-2026-73314
XenForo before 2.3.13 contains a signature verification logic error in the PayPal REST webhook handler that allows unauthenticated attackers to bypass payment s
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.
Affected Products
- xenforo/xenforo
References
- https://bombobombone.github.io/posts/cve-2026-73314/
- https://github.com/BomboBombone/CVE-2026-73314
- https://www.vulncheck.com/advisories/xenforo-signature-verification-bypass-via-paypal-rest
- https://xenforo.com/community/threads/security-fixes-released-for-all-xenforo-and-media-ga
- https://xenforo.com/community/threads/xenforo-2-3-13-and-add-ons-released-includes-securit
This high severity vulnerability with a CVSS score of 8.7 was published on 2026-09-08 via NVD. Affected: xenforo/xenforo.
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