CVE-2026-18422: Auth Bypass

Description

Concrete CMS before 9.5.3 did not enforce a destination-side authorization check and did not validate a CSRF token in the multilingual page assignment backend action (Backend\Page\Multilingual::assign). As a result, an authenticated user who held the Edit Page Multilingual Settings permission on a single page could bind an arbitrary page in another locale as that source page's translation, and could delete legitimate translation pairs maintained by other editors, altering public-facing language routing across the site. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.1 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N. Thanks Winston Crooker for reporting.

Is your site exposed to CVE-2026-18422?

Run a free security scan — no signup, results in seconds.

Weakness Type (CWE)

CWE-862 Missing Authorization

References

Other References

https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes

Frequently Asked Questions

What is CVE-2026-18422? +

Concrete CMS before 9.5.3 did not enforce a destination-side authorization check and did not validate a CSRF token in the multilingual page assignment backend action (Backend\Page\Multilingual::assign). As a result, an authenticated user who held the Edit Page Multilingual Settings permission on a single page could bind an arbitrary page in another locale as that source page's translation, and could delete legitimate translation pairs maintained by other editors, altering public-facing language routing across the site. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.1 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N. Thanks Winston Crooker for reporting.

How do I check if I'm vulnerable to CVE-2026-18422? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-40570

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, the `load_customer_info` action in `POST /conversation/ajax` …

CVE-2026-42317

GLPI is a free asset and IT management software package. Starting in version 0.78 and prior to versions 10.0.25 and …

CVE-2026-4881

In affected versions of Octopus Server, permissions were not checked correctly resulting in any authenticated user being able to make …

CVE-2026-40543

SOPlanning does not enforce authorization for backup functionalities. An unauthenticated attacker can directly query backup-related endpoints and retrieve backup archives …

CVE-2026-10831

A denial-of-service vulnerability exists in NPort devices because of improper access control on the command port. The command interface does …

CVE-2026-40314

NamelessMC is website software for Minecraft servers. In version 2.2.4,`core/classes/Misc/ProfilePostReactionContext.php` only verifies that the wall post exists and does not …

CVE-2026-18422