CVE-2026-41203 ci4ms Theme::upload is vulnerable to Zip Slip leading to RCE
Authenticated users with theme creation permissions can achieve remote code execution via Zip Slip in the theme upload feature.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-41203?
CVE-2026-41203 is a critical path traversal vulnerability in ci4-cms-erp ci4ms, published on 7 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
CI4MS is a CodeIgniter 4-based CMS skeleton that delivers a production-ready, modular architecture with RBAC authorization and theme support. Prior to version 0.31.5.0, ci4ms Theme::upload extracts user uploaded ZIP archives without validating entry names, allowing an authenticated backend user with the theme create permission to write files to arbitrary filesystem locations (Zip Slip) and achieve remote code execution by dropping a PHP file under the public web root. This issue has been patched in version 0.31.5.0.
Weakness: CWE-22
Which versions are affected by CVE-2026-41203?
2 open source packages ship an affected version, including ci4-cms-erp/ci4ms.
| Package | Affected | Fixed in |
|---|---|---|
ci4-cms-erp/ci4ms Packagist | All versions | 0.31.5.0 |
ci4-cms-erp/ci4ms Packagist | All versions | 0.31.5.0 |
How do I fix CVE-2026-41203?
Upgrade ci4-cms-erp/ci4ms to 0.31.5.0 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-41203 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-41203 exists.
Sources
Also known as GHSA-xv3r-vr59-95rg.