XSS in Xenforo
CVE-2026-73319
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.
Vulnerability class: XSS (Cross-Site Scripting)
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- disclosure@vulncheck.com (vendor-advisory, patch)
- disclosure@vulncheck.com (release-notes)
- disclosure@vulncheck.com (third-party-advisory)
- disclosure@vulncheck.com (technical-description)
- disclosure@vulncheck.com (exploit)
Frequently asked questions
- What is CVE-2026-73319?
- CVE-2026-73319 is a medium-severity vulnerability in Xenforo, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-09-08.
- How severe is CVE-2026-73319?
- Medium severity. CVSS v3 base score is 6.1 out of 10.
- Is CVE-2026-73319 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.