Quick answers
- Is CVE-2026-55794 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-55794 being exploited in the wild.
- How severe is CVE-2026-55794?
- High severity, with a CVSS score of 4, published 2 July 2026.
- Which products and versions are affected?
- craftcms/cms (Packagist) >= 5.9.0, < 5.10.0, ECOSYSTEM:introduced=5.9.0,fixed=5.10.0.
- Is there a fix for CVE-2026-55794?
- Yes. craftcms/cms (Packagist): upgrade to 5.10.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-55794 attacked?
- It is attacked over the network, in a network appliance.
- Am I affected by CVE-2026-55794?
- Check whether you run craftcms/cms (Packagist) 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.
How to fix
- craftcms/cms (Packagist): upgrade to 5.10.0 or later
composer require craftcms/cms:^5.10.0
Technical details
A Server-Side Template Injection (SSTI) vulnerability exists in Craft CMS versions 5.9.x prior to 5.10.0. The application uses the `renderObjectTemplate()` function to process strings for signed redirect URLs derived from the 'Referer' HTTP header. Because this function does not enforce sandboxing, an authenticated attacker with 'edit entry' permissions can inject malicious Twig templates into the Referer header. When the entry is saved, the template is executed on the server, leading to Remote Code Execution (RCE). The fix involves migrating to `renderSandboxedObjectTemplate()` and explicitly setting return URLs.
Affected products
- Craft CMS CMS >= 5.9.0, < 5.10.0
Identifiers
- CVE-2026-55794
- GHSA-f74w-488g-8x5r
Timeline
- 2026-04-17: patched: Pull request merged into version 5.10
- 2026-07-01: disclosed: NVD publication date
- 2026-07-06: advisory: GitHub Advisory published