CVE-2026-115935 Control panel only API response emulation replaces "securityKey" and reaches server RCE
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-115935?
CVE-2026-115935 is a high-severity vulnerability in craftcms cms, published on 23 Oct 2026.
Official description
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.
Weakness: CWE-94
Which versions are affected by CVE-2026-115935?
How do I fix CVE-2026-115935?
Upgrade to a fixed version.
Is CVE-2026-115935 being exploited?
There is no known exploitation of CVE-2026-115935 in the wild and no public exploit code.
Sources
Also known as GHSA-9hp6-3565-gvh5, GHSA-j6hf-w48h-c9f9.