CVE-2026-73319 XenForo < 2.3.13 XSS via Dynamic Redirect Handler

What is CVE-2026-73319?

CVE-2026-73319 is a medium-severity cross-site scripting vulnerability in XenForo, published on 8 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

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.

Weakness: CWE-79

Which versions are affected by CVE-2026-73319?

It affects 1 product.

Products include Xenforo Xenforo.

How do I fix CVE-2026-73319?

No fix has been published for CVE-2026-73319 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2026-73319 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-73319 exists.

Public exploit code: 1 proofs of concept on GitHub.

Other vulnerabilities in XenForo

• CVE-2025-71279 XenForo Passkey Security Bypass Critical 9.3
• CVE-2026-73309 XenForo < 2.3.13 Authentication Bypass via OAuth2 Token Endpoint Critical 9.1
• CVE-2026-73311 XenForo < 2.3.13 OAuth2 Authorization Code Reuse Critical 9.1
• CVE-2026-73312 XenForo < 2.3.13 Refresh Token Replay via Expired Access Token Critical 9.1
• CVE-2024-38457 Xenforo before 2.2.16 allows CSRF. High 8.8

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-vggm-cwh9-fm3v.