Vulnerability · Published Apr 20, 2026 · Assigned by GitHub_M

CVE-2026-40488OpenMage LTS has Customer File Upload Extension Blocklist Bypass that Leads to Remote Code Execution

High 8.7

In plain English

A high-severity unrestricted file upload in magento-lts from OpenMage. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 53% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)8.7High

Exploit odds (30 days)0.7%top 47.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Magento Long Term Support (LTS) is an unofficial, community-driven project provides an alternative to the Magento Community Edition e-commerce platform with a high level of backward compatibility. Prior to version 20.17.0, the product custom option file upload in OpenMage LTS uses an incomplete blocklist (`forbidden_extensions = php,exe`) to prevent dangerous file uploads. This blocklist can be trivially bypassed by using alternative PHP-executable extensions such as `.phtml`, `.phar`, `.php3`, `.php4`, `.php5`, `.php7`, and `.pht`. Files are stored in the publicly accessible `media/custom_options/quote/` directory, which lacks server-side execution restrictions for some configurations, enabling Remote Code Execution if this directory is not explicitly denied script execution. Version 20.17.0 patches the issue.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Packagist	openmage/magento-lts	20.17.0	GHSA-3j5q-7q7h-2hhv

Affected products (as reported)

Vendor	Product	Versions
OpenMage	magento-lts	< 20.17.0

Weakness: CWE-434 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

References

https://github.com/OpenMage/magento-lts/security/advisories/GHSA-3j5q-7q7h-2hhv x_refsource_CONFIRM