What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-09-08 · updated 2026-09-11
• Weakness: CWE-79

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.

Affected products

• XenForo: before 2.3.13 — fixed in 2.3.13

How to fix

Upgrade to a fixed version: XenForo 2.3.13. Check the vendor advisory for mitigations.

References

• https://bombobombone.github.io/posts/cve-2026-73319/
• https://github.com/BomboBombone/CVE-2026-73319
• https://www.vulncheck.com/advisories/xenforo-xss-via-dynamic-redirect-handler
• 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/

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