---
id: CVE-2026-73315
title: >-
  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…
summary: >-
  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…
severity: high
cvss: 8.6
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N'
cwe:
  - CWE-918
vendor: xenforo
product: xenforo
affected:
  - xenforo < 2.3.13
patched:
  - xenforo 2.3.13
published: '2026-09-08'
updated: '2026-09-11'
sourceUpdated: '2026-09-11T20:31:26.440'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73315'
references:
  - url: 'https://bombobombone.github.io/posts/cve-2026-73315/'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/BomboBombone/CVE-2026-73315'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/xenforo-ssrf-via-paypal-rest-webhook-handler
    label: disclosure@vulncheck.com
  - url: >-
      https://xenforo.com/community/threads/security-fixes-released-for-all-xenforo-and-media-gallery-versions-2-2-0-2-3-12.239856/
    label: disclosure@vulncheck.com
  - url: >-
      https://xenforo.com/community/threads/xenforo-2-3-13-and-add-ons-released-includes-security-fixes.239857/
    label: disclosure@vulncheck.com
tags:
  - nvd
  - exploit-available
  - cve.org
epss: 0.00357
epssPercentile: 0.26908
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/BomboBombone/CVE-2026-73315'
  checkedAt: '2026-09-27T10:33:58.442Z'
exploitAvailable: true
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-08T13:42:15.724503Z'
ingestedAt: '2026-09-08T15:33:26.984Z'
---

## Overview

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

- `xenforo < 2.3.13`

## Remediation

Upgrade past the affected range:

- `xenforo 2.3.13`