CVE-2026-73314
8.7
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Summary
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 Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| XenForo | XenForo | 0 < 2.3.13 | affected |
Weaknesses
- CWE-754: Improper Check for Unusual or Exceptional Conditions
References
- https://xenforo.com/community/threads/security-fixes-released-for-all-xenforo-and-media-gallery-versions-2-2-0-2-3-12.239856/
- https://xenforo.com/community/threads/xenforo-2-3-13-and-add-ons-released-includes-security-fixes.239857/
- 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-webhook
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