CVE-2026-73319

EUVD-2026-72756

08.09.2026, 14:17

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.

Cross-site Scripting

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
NIST	Primary	6.1 MEDIUM	NETWORK	LOW	NONE	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Base Score

CVSS 3.x

EPSS Score

Percentile: 34.36%

Affected Products (NVD)

Vendor	Product	Version
xenforo	xenforo	𝑥 < 2.3.13

𝑥

= Vulnerable software versions

Known Exploits!

Common Weakness Enumeration

CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

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/