CVE-2026-2735 Stored Cross-Site Scripting (XSS) vulnerability in Alkacon's OpenCms

Medium 5.1 Published 19 Feb 2026 Updated 20 Feb 2026

Attackers can inject malicious scripts via the blog article text field, potentially stealing user sessions or executing code in victim browsers.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2026-2735?

CVE-2026-2735 is a medium-severity cross-site scripting vulnerability in Alkacon OpenCms, published on 19 Feb 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

Official description

Stored Cross-Site Scripting (XSS) in Alkacon's OpenCms v18.0, which occurs when user input is not properly validated when sending a POST request to ‘/blog/new-article/org.opencms.ugc.CmsUgcEditService.gwt’ using the ‘text’ parameter.

Weakness: CWE-79

Which versions are affected by CVE-2026-2735?

It affects 1 product.

Products include Alkacon Opencms.

How do I fix CVE-2026-2735?

No fix has been published for CVE-2026-2735 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-2026-2735 being exploited?

There is no known exploitation of CVE-2026-2735 in the wild and no public exploit code.

Sources

Also known as GHSA-74m2-9pf8-f794.