Track vulnerabilities like this one.
Sign up free to get alerted when software you use is affected.
9.4
CVE-2026-115935: Craft CMS control panel user can replace security key
CVE-2026-115935 · published 12 days ago
Summary
A user who can log into the Craft CMS control panel can send specially crafted API headers that change the secret security key stored in the site's .env file. With the new key the attacker can create forged login redirects and gain full access to the site. Update Craft to the latest patched version and restrict control‑panel access to trusted administrators.
What to do
- Update craftcms cms to version 5.11.2 or later.
Affected software
| Vendor | Product | Affected versions |
|---|---|---|
| craftcms | cms | < 5.11.2 |
Original advisory text
Control panel only API response emulation replaces "securityKey" and reaches server RCE
The app/process-api-response-headers action accepts fake Craft API response headers from any authenticated control panel user.
A non-admin user with only accessCp can place newline characters in X-Craft-Plugin-Licenses. Craft passes this value to its .env writer without removing the newlines.
This lets the user insert a new attacker-known CRAFT_SECURITY_KEY into .env. After Craft loads that key, the user can forge a signed login redirect containing a Twig system() callback.
This is different from the previous report. That report reads the existing key through a Twig sandbox bypass. This report replaces the key through fake API headers and CRLF injection. Fixing either source does not fix the other.
A non-admin user with only accessCp can place newline characters in X-Craft-Plugin-Licenses. Craft passes this value to its .env writer without removing the newlines.
This lets the user insert a new attacker-known CRAFT_SECURITY_KEY into .env. After Craft loads that key, the user can forge a signed login redirect containing a Twig system() callback.
This is different from the previous report. That report reads the existing key through a Twig sandbox bypass. This report replaces the key through fake API headers and CRLF injection. Fixing either source does not fix the other.
References
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/115xxx/CVE-2026-1159... Vendor Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2026-115935 Vendor Advisory
- https://packagist.org URL
- https://github.com/craftcms/cms Product
- https://github.com/craftcms/cms/releases/tag/5.11.2 Vendor Advisory
- https://github.com/craftcms/cms/security/advisories/GHSA-9hp6-3565-gvh5 Vendor Advisory
- https://www.hckrt.com/hacktivity/HCKRT-WM3VSE Vendor Advisory
Internet-facing
14 days
Internal
At next upgrade
- Not known to be exploited
- Needs hands-on effort to exploit
- Gives an attacker full control
Severity
9.4
Critical
Type
CWE-94Code Injection
Timeline
Published23 Oct 2026
Updated4 Nov 2026
First seen23 Oct 2026
Sources
CVE-2026-115935 · NVD
CVE-2026-115935 · MITRE
CVE-2026-115935 · OSV
GHSA-9hp6-3565-gvh5 · GHSA
Track software like this
Free during beta