# CVE-2026-81926: Concrete CMS stored XSS in page path duplicate dialog

Source: https://junglewise.ai/threats/cve-2026-81926-concrete-cms-stored-xss-in-page-path-duplicate-dialog  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-15. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-81926 · Severity: medium · CVSS 6.1 · Published 2026-09-15

Concrete CMS is a website management platform used to build and maintain content-driven websites. An authenticated editor with administrative privileges can inject malicious JavaScript into page paths, which executes in the browser of other editors viewing the duplicate-path confirmation dialog. This allows attackers to steal session credentials, modify pages, or perform actions on behalf of legitimate users within the CMS.

Technologies: [Concrete CMS](https://junglewise.ai/threats/technologies/concrete-cms). Vendors: [Concrete CMS](https://junglewise.ai/threats/vendors/concrete-cms).

## Quick answers

**Is CVE-2026-81926 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-81926 being exploited in the wild.

**How severe is CVE-2026-81926?** Medium severity, with a CVSS score of 6.1, published 15 September 2026.

**Which products and versions are affected?** Concrete CMS 9.4.0 through 9.5.2.

**Is there a fix for CVE-2026-81926?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-81926 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-81926?** Check whether you run Concrete CMS at an affected version. 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

This is a stored/reflected cross-site scripting (XSS) vulnerability in the page location panel's duplicate-path confirmation dialog. The root cause is improper output encoding: the panel's check endpoint returns a user-supplied page path unmodified in its JSON response, and client-side JavaScript then inserts this value directly into the dialog as raw HTML without escaping. An authenticated editor with sufficient privileges can craft a malicious page path containing script tags (e.g., <script>...</script>) that will execute in the browser of any other user who views the duplicate-path confirmation. No special preconditions are needed beyond authentication and editor-level permissions. An attacker can execute arbitrary JavaScript in the victim's authenticated session context, potentially leading to credential theft, unauthorized content modification, or further lateral movement within the CMS. Patches addressing output encoding are available in versions after 9.5.2.

## Affected products

- Concrete CMS Concrete CMS 9.4.0 through 9.5.2

## Timeline

- 2026-09-15: disclosed
- other: CVE-2026-81926 assigned

## References

- [https://github.com/concretecms/concretecms](https://github.com/concretecms/concretecms)
- [https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes](https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes)

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