{"id":"CVE-2026-73314","revision":"35ea7ea2bd66450fbaf89e9f32c91435","records":[{"revision":"35ea7ea2bd66450fbaf89e9f32c91435","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-73314","aliases":[],"title":"XenForo < 2.3.13 Signature Verification Bypass via PayPal REST Webhook","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.","state":0,"publishedAt":"2026-09-08T13:17:52.339+00:00","modifiedAt":"2026-10-01T15:20:34.739+00:00","affected":[{"ecosystem":"Vendor product","name":"XenForo","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"defaultStatus\": \"unaffected\",\n                    \"vendor\": \"XenForo\",\n                    \"product\": \"XenForo\",\n                    \"versions\": [\n                        {\n                            \"status\": \"affected\",\n                            \"version\": \"0\",\n                            \"versionType\": \"semver\",\n                            \"lessThan\": \"2.3.13\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 4.0","vector":"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","score":8.7,"severity":"HIGH"},{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","score":7.5,"severity":"HIGH"}],"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"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-73314","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-73314","identifiers":["CVE-2026-73314"]},"retained":false,"historicalAffected":[]}],"coverage":[]}