CVE-2026-73314
highXenForo before 2.3.13 contains a signature verification logic error in the PayPal REST webhook handler that allows unauthenticated attackers to bypass payment…
Vendor / product: Xenforo — xenforo
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Affected products
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://bombobombone.github.io/posts/cve-2026-73314/ disclosure@vulncheck.com
- https://github.com/BomboBombone/CVE-2026-73314 disclosure@vulncheck.com
- https://www.vulncheck.com/advisories/xenforo-signature-verification-bypass-via-paypal-rest... disclosure@vulncheck.com
- https://xenforo.com/community/threads/security-fixes-released-for-all-xenforo-and-media-ga... disclosure@vulncheck.com
- https://xenforo.com/community/threads/xenforo-2-3-13-and-add-ons-released-includes-securit... disclosure@vulncheck.com