Is CVE-2026-74239 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-74239 being exploited in the wild.

How severe is CVE-2026-74239?

High severity, with a CVSS score of 7.2, published 8 September 2026.

Is there a fix for CVE-2026-74239?

A patch was published on 2026-09-08: XenForo 2.3.13 released with fix Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-74239 attacked?

It is attacked over the network, in a web application.

Am I affected by CVE-2026-74239?

Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-74239: XenForo path traversal in style archive importer on Windows

CVE-2026-74239 · Severity: high · CVSS 7.2 · Published 2026-09-08

XenForo is a community forum software platform. A flaw in its style archive import feature on Windows allows authenticated administrators with styling permissions to write malicious code to the web server's public directory, achieving persistent code execution. An attacker with delegated style management rights can upload a specially crafted archive to take over the forum and access sensitive user data.

Quick answers

Is CVE-2026-74239 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-74239 being exploited in the wild.
How severe is CVE-2026-74239?: High severity, with a CVSS score of 7.2, published 8 September 2026.
Which products and versions are affected?: XenForo XenForo before 2.3.13.
Is there a fix for CVE-2026-74239?: A patch was published on 2026-09-08: XenForo 2.3.13 released with fix Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-74239 attacked?: It is attacked over the network, in a web application.
Am I affected by CVE-2026-74239?: Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

XenForo's style archive importer validates ZIP member paths by rejecting forward-slash traversal sequences (/../) but fails to normalize or reject backslashes on Windows, where backslash is the path separator. An authenticated non-super administrator with style permissions can craft a malicious ZIP archive with backslash-based traversal sequences (such as upload/..\..\..\..\path\to\target) that bypass validation and write arbitrary files outside the intended extraction directory. Windows interprets these backslash sequences as directory separators during extraction, allowing the attacker to write PHP files to the web root or other writable locations. This enables persistent remote code execution as the web-server process account. The vulnerability affects XenForo versions before 2.3.13, which corrected archive-path validation logic.

Affected products

XenForo XenForo before 2.3.13

Timeline

2026-09-08: disclosed
2026-09-08: patched: XenForo 2.3.13 released with fix

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.