How severe is CVE-2026-40488?

No CVSS score has been assigned to CVE-2026-40488 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-40488?

CVE-2026-40488 affects the following packages: openmage/magento-lts (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-40488?

Update openmage/magento-lts to 20.17.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40488 is resolved across your whole dependency graph.

How do I detect CVE-2026-40488 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for openmage/magento-lts. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-40488 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-40488?

O3 pinpoints whether CVE-2026-40488 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-40488 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-40488 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was CVE-2026-40488 published, and has it been updated?

CVE-2026-40488 was published on April 20, 2026 and was last updated on August 7, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

CVE-2026-40488

CVE-2026-40488 is a remote code execution vulnerability in openmage/magento-lts. O3 Security confirms whether CVE-2026-40488 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

OpenMage LTS has Customer File Upload Extension Blocklist Bypass that Leads to Remote Code Execution

Also known asGHSA-3j5q-7q7h-2hhv

Published

Apr 20, 2026

Updated

Aug 7, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Blast Radius

1 pkg affected

🐘openmage/magento-lts

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

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

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`openmage/magento-lts`	all versions	20.17.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for openmage/magento-lts. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update openmage/magento-lts to 20.17.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40488 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-40488 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-40488. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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_opt

O3 Security · Impact-Aware SCA

Is CVE-2026-40488 in your dependencies?

O3 detects CVE-2026-40488 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works