craftcms/cms security advisory

CVE-2026-55793: Craft CMS: Stored XSS via Structure entry title in table view

CVE-2026-55793 is a medium-severity stored XSS vulnerability in the PHP package craftcms/cms (CVSS 5.9), published 1 July 2026. It is fixed in 5.9.22; earlier versions are affected. Exploiting it needs a low-privilege user account.

medium 5.9 published 2026-07-01 · updated 2026-10-25

Affected versions: >= 5.0.0-RC1, < 5.9.22
Fixed in: 5.9.22
Newest release: 5.12.0
Severity: Medium · CVSS 5.9
Type: Stored cross-site scripting (XSS)
CWE-79
Exploited in the wild: Not on the CISA KEV list
checked 2026-11-04

Is your craftcms/cms version affected?

Run composer show craftcms/cms in your project, then enter the version. We check it against this and every other known craftcms/cms advisory.

Who can exploit CVE-2026-55793

Access: A normal, low-privilege user account in the app.
Interaction: A user also has to do something, such as open a link or a page the attacker prepared.
Conditions: It only works under specific conditions the attacker does not fully control (CVSS rates the attack as high complexity).

CVSS vector (scored by GitHub): CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Your app is only exposed if it uses the affected part of craftcms/cms. The advisory below says which part that is. If you are not sure, upgrade anyway: it costs less than finding out.

How to fix CVE-2026-55793 in craftcms/cms

Find the installed version: composer show craftcms/cms. If you never required it yourself, composer why craftcms/cms shows which package pulls it in.
Update it: composer update craftcms/cms --with-all-dependencies. You need 5.9.22 or newer.
If Composer will not go that high, your composer.json constraint is holding it back. Widen it (for example "craftcms/cms": "^5.9.22" if you can take that version), or upgrade the package that requires it.
Run composer audit. It reads the same advisory data and should no longer list CVE-2026-55793.
Commit composer.lock and deploy it. On the server, run composer install --no-dev from the lock file, not composer update.

If you cannot upgrade yet

General hardening for stored XSS issues while the upgrade waits. None of it replaces the fix.

Escape output in your own templates and add a Content-Security-Policy that blocks inline scripts.
Limit who can save the content the advisory names (for example rich text, SVG or form fields).
If your app does not use the affected feature, note that in your audit, but still plan the upgrade.

The CVE-2026-55793 advisory

Craft CMS is a content management system (CMS). In versions 5.0.0-RC1 through 5.9.22, an author-level control panel user can store a malicious JavaScript payload in an entry title. When an admin, or any control panel user with saveEntries for the same Structure section, drags another entry under the poisoned entry in table view, the payload executes in the victim’s session. The issue is exploitable because the title is escaped into data-title by the server, decoded again by the browser, read with jQuery .data('title'), and then concatenated into a new HTML string without attribute escaping. To exploit, an attacker must have an existing control panel account (Author role minimum), the victim must perform a drag operation (not just visit the page), and the victim’s session needs to be elevated at trigger time. This issue has been fixed in version 5.9.23.

Description from the CVE record, published by GitHub (the CVE Numbering Authority), via the NVD entry for CVE-2026-55793. Advisory title: “Craft CMS: Stored XSS via Structure entry title in table view”.

References

GitHub advisory GHSA-xrqc-p465-2xvg github.com
Fix commit 162321e github.com

Other craftcms/cms advisories

critical Craft CMS: Passkey login accepts replayed WebAuthn assertions 2026-08-07
medium CVE-2026-72779: Craft CMS: Arbitrary file read via SplFileObject in non-sandboxed template contexts 2026-08-06
medium CVE-2026-72782: Craft CMS: Authenticated leak of secret environment variables 2026-08-06
medium CVE-2026-72785: Craft CMS: Authorization bypass: view-only Categories user can modify category structure via structures/move-element 2026-08-06
medium CVE-2026-14794: Craft CMS: Missing authorization check allows non-admin control panel users access to user registration metrics 2026-08-06
low CVE-2026-72783: Craft CMS: Incorrect path validation could potentially lead to path traversal 2026-08-06

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Where this data comes from

Affected and fixed versions: the Packagist security advisories API (GitHub Advisory Database and FriendsOfPHP), the same data composer audit uses. Synced 2026-11-03.
Description, score, weakness and references: NIST National Vulnerability Database (NVD), checked 2026-11-04. This product uses data from the NVD API but is not endorsed or certified by the NVD.
Exploited-in-the-wild status: the CISA Known Exploited Vulnerabilities catalog, checked 2026-11-04.
Compiled by Daniel Lasek at Laskyr from the sources above. The summary, “who can exploit it”, “how to fix it” and hardening sections are our plain-English reading of the record and are generated from it. The quoted description is the record's own text. Spot an error? Tell us.