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Fencer Intel
high 8.8

CVE-2026-40488 json

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

published 6mo ago modified 14d ago also EUVD-2026-23904 , GHSA-3j5q-7q7h-2hhv

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 53%
public exploits
0
none known

Summary

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.

Patch / fix

  • packagist openmage/magento-lts 20.17.0
  • openmage magento 20.17.0
  • openmage openmage 20.17.0

Is CVE-2026-40488 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
6mo ago

Exploit prediction

0.69% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/OpenMage/magento-lts/security/advisories/GHSA-3j5q-7q7h-2hhv referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.7 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
GitHub 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA 4.0 8.7 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/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
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
packagist openmage/magento-lts
<20.17.0
20.17.0

Affected products

  • OpenMage magento-lts

Classification

Weakness
  • CWE-434 Unrestricted Upload of File with Dangerous Type

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.