CVE-2026-81898 Cross-site scripting in Concrete CMS
Attackers can inject malicious scripts via Address attributes in Concrete CMS, potentially hijacking dashboard user sessions.
- 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-2026-81898?
CVE-2026-81898 is a high-severity cross-site scripting vulnerability in Concrete CMS, published on 15 Sep 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
In Concrete CMS below version 9.5.3, the Address attribute's country-less text formatter skipped HTML-escaping, enabling stored XSS in Express association views. A user able to submit an Address attribute could execute script in the session of any dashboard user who opened the affected entry. The unescaped branch was reachable because a non-required Address attribute accepted a blank country, and because several Express association templates (for example concrete/elements/express/form/view/dashboard/association.php) echoed the association label mask without applying h(). The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.
Weakness: CWE-79
Which versions are affected by CVE-2026-81898?
How do I fix CVE-2026-81898?
No fix has been published for CVE-2026-81898 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-2026-81898 being exploited?
There is no known exploitation of CVE-2026-81898 in the wild and no public exploit code.
Sources
Also known as GHSA-fvp6-f7j9-p236.