---
id: CVE-2026-73319
title: >-
  XenForo before 2.3.13 contains a cross-site scripting vulnerability in the
  dynamic redirect handler that allows unauthenticated attackers to execute
  arbitrary JavaScript in the board origin by crafting a malicious javascript:
  URI that by…
summary: >-
  XenForo before 2.3.13 contains a cross-site scripting vulnerability in the
  dynamic redirect handler that allows unauthenticated attackers to execute
  arbitrary JavaScript in the board origin by crafting a malicious javascript:
  URI that by…
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'
cwe:
  - CWE-79
vendor: xenforo
product: xenforo
affected:
  - xenforo < 2.3.13
patched:
  - xenforo 2.3.13
published: '2026-09-08'
updated: '2026-09-11'
sourceUpdated: '2026-09-11T20:26:33.740'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73319'
references:
  - url: 'https://bombobombone.github.io/posts/cve-2026-73319/'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/BomboBombone/CVE-2026-73319'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/xenforo-xss-via-dynamic-redirect-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: 0.00412
epssPercentile: 0.32811
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/BomboBombone/CVE-2026-73319'
  checkedAt: '2026-09-26T09:05:58.810Z'
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-10T13:47:02.889081Z'
ingestedAt: '2026-09-08T15:33:26.984Z'
---

## Overview

XenForo before 2.3.13 contains a cross-site scripting vulnerability in the dynamic redirect handler that allows unauthenticated attackers to execute arbitrary JavaScript in the board origin by crafting a malicious javascript: URI that bypasses host validation. Attackers can embed the board hostname in the URI authority component and use percent-encoded newlines to evade server-side filters, causing authenticated users who perform a Follow action to execute attacker-supplied JavaScript in their browser.

## Affected

- `xenforo < 2.3.13`

## Remediation

Upgrade past the affected range:

- `xenforo 2.3.13`