CVE-2026-115935
published 2026-10-23CVE-2026-115935: 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…
PriorityP356high8.8CVSS 3.1
AVNACLPRLUINSUCHIHAH
EPSS
0.37%
30.6th percentile
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.
Affected
2 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| craftcms | cms | >= 4.0.0 < 4.18.9 | 4.18.9 |
| craftcms | cms | >= 5.0.0 < 5.11.2 | 5.11.2 |
CVSS provenance
nvdv3.18.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvdv4.08.7HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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VulDB
Craft CMS up to 4.18.8/5.11.1 Process API Response Headers system X-Craft-Plugin-Licenses crlf injection (EUVD-2026-109191)
vuldb·2026-10-24·CVSS 8.8
CVE-2026-115935 [HIGH] Craft CMS up to 4.18.8/5.11.1 Process API Response Headers system X-Craft-Plugin-Licenses crlf injection (EUVD-2026-109191)
A vulnerability described as critical has been identified in Craft CMS up to 4.18.8/5.11.1. Impacted is the function system of the component Process API Response Headers. Executing a manipulation of the argument X-Craft-Plugin-Licenses can lead to crlf injection.
This vulnerability is handled as CVE-2026-115935. The attack can be executed remotely. There is not any exploit available.
Upgrading the affected component is recommended.
GHSA
The app/process-api-response-headers action accepts fake Craft API response headers from any authenticated control panel user.
ghsa_unreviewed·2026-10-24
CVE-2026-115935 [HIGH] CWE-94 The app/process-api-response-headers action accepts fake Craft API response headers from any authenticated control panel user.
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.
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2026-10-23
Published