Vulnerability · Published Sep 8, 2026 · Assigned by VulnCheck

CVE-2026-73315XenForo < 2.3.13 SSRF via PayPal REST Webhook Handler

High 8.6

In plain English

A high-severity server-side request forgery in XenForo from XenForo. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 30% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.

Severity (CVSS 3.1)8.6High

Exploit odds (30 days)0.4%top 70.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack tooling1Public PoC

Official description

XenForo before 2.3.13 contains a server-side request forgery vulnerability in the PayPal REST webhook handler that allows unauthenticated attackers to cause the server to make outbound HTTP requests to arbitrary destinations by supplying a crafted certificate URL in webhook headers without scheme, hostname, or allowlist validation. Attackers can submit a crafted POST to the PayPal webhook callback endpoint to reach internal network resources including cloud instance metadata services, potentially disclosing IAM credentials or enabling secondary internal service exploitation.

Affected products (as reported)

Vendor	Product	Versions
XenForo	XenForo	0 – before 2.3.13

Weakness: CWE-918 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

References

Vendor Advisory vendor-advisory, patch
Release Notes release-notes
Researcher Advisory technical-description
Researcher PoC exploit
https://www.vulncheck.com/advisories/xenforo-ssrf-via-paypal-rest-webhook-handler third-party-advisory