All vulnerabilities
CVE-2026-104890GHSA-p279-5wcv-45vq

kunstmaan/media-bundle: Kunstmaan CMS: MediaBundle extension blacklist bypass allows authenticated administrators to upload executable PHP files leading to remote code execution

Kunstmaan kunstmaan/media-bundlecomposerLibraries & packages
Open in ThreatlineRecord JSON
CVSS
7.2High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.42%Chance of exploitation activity in the next 30 days, higher than 34% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in7.3.2Fixed versionGitHub
Published5 Oct 2026Updated 7 Oct 2026CVE List

What fixes it

  • 7.3.2kunstmaan/media-bundle, composerGitHubcomposer require "kunstmaan/media-bundle:^7.3.2"
  • 7.3.2kunstmaan/bundles-cms, composerGitHubcomposer require "kunstmaan/bundles-cms:^7.3.2"
  • 7.3.2kunstmaan/media-bundle, PackagistOSVcomposer require "kunstmaan/media-bundle:^7.3.2"
  • 7.3.2kunstmaan/bundles-cms, PackagistOSVcomposer require "kunstmaan/bundles-cms:^7.3.2"

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

Summary

The MediaBundle blocks dangerous upload extensions with a blacklist that was matched case-sensitively, while the stored filename was lowercased afterwards. A file uploaded as webshell.pHp therefore bypassed the blacklist and was written to the web-accessible upload directory as webshell.php, where the web server executed it. Any authenticated backend user with access to the media section could obtain remote code execution.

Details

FileHandler::getFilePath() rewrote blacklisted extensions to .txt using a case-sensitive regex, and only then lowercased the extension when building the stored name — so the check ran against the attacker-controlled casing and the normalisation happened after it.

Two further weaknesses contributed:

  • The default blacklist contained only php and htaccess, leaving other

server-executable extensions (phtml, php5, phar, shtml, cgi, …) unblocked regardless of casing.

  • Configured blacklist values were interpolated into the regex unescaped.

Impact

An authenticated user with access to the admin media section can upload a file that the web server executes as PHP. The uploaded file is reachable over HTTP without authentication, giving arbitrary code execution as the web server user.

Patches

Fixed in kunstmaan/media-bundle 7.3.2. The extension is now normalised before it is checked and compared with in_array(); the default blacklist is expanded to the full set of server-executable extensions; and a new opt-in allowed_extensions option allows projects to enforce a strict allow-list.

Note that the patch does not rename files already stored on disk. Sites should audit their media upload directory for existing files with an executable extension.

Workarounds

If you cannot upgrade, configure the web server to refuse to execute scripts in the media upload directory (for example a location block in nginx or php_flag engine off in Apache).

Text from GitHub Advisory Database

Affected versions 107

  • kunstmaan/media-bundle, composer< 7.3.2GitHub
  • kunstmaan/bundles-cms, composer< 7.3.2GitHub
  • KunstmaanBundlesCMSaffected: < 7.3.1CVE List
  • bundles-cmsaffected: < 7.3.1CVE List
  • media-bundleaffected: < 7.3.1CVE List
  • kunstmaan/media-bundle, Packagistfrom first release, fixed in 7.3.2OSV
  • kunstmaan/media-bundle, Packagist3.0.0OSV
  • kunstmaan/media-bundle, Packagist3.0.1OSV
  • kunstmaan/media-bundle, Packagist3.0.2OSV
  • kunstmaan/media-bundle, Packagist3.0.3OSV
  • kunstmaan/media-bundle, Packagist3.1.0OSV
  • kunstmaan/media-bundle, Packagist3.1.1OSV
  • kunstmaan/media-bundle, Packagist3.1.2OSV
  • kunstmaan/media-bundle, Packagist3.1.3OSV
  • kunstmaan/media-bundle, Packagist3.1.4OSV
  • kunstmaan/media-bundle, Packagist3.2.0OSV
  • kunstmaan/media-bundle, Packagist3.2.1OSV
  • kunstmaan/media-bundle, Packagist3.2.1.1OSV
  • kunstmaan/media-bundle, Packagist3.2.2OSV
  • kunstmaan/media-bundle, Packagist3.2.3OSV
  • kunstmaan/media-bundle, Packagist3.2.4OSV
  • kunstmaan/media-bundle, Packagist3.2.4.1OSV
  • kunstmaan/media-bundle, Packagist3.2.5OSV
  • kunstmaan/media-bundle, Packagist3.2.6OSV
  • kunstmaan/media-bundle, Packagist3.3.0OSV
  • kunstmaan/media-bundle, Packagist3.3.1OSV
  • kunstmaan/media-bundle, Packagist3.3.2OSV
  • kunstmaan/media-bundle, Packagist3.3.3OSV
  • kunstmaan/media-bundle, Packagist3.3.4OSV
  • kunstmaan/media-bundle, Packagist3.4.0OSV
  • kunstmaan/media-bundle, Packagist3.4.1OSV
  • kunstmaan/media-bundle, Packagist3.4.2OSV
  • kunstmaan/media-bundle, Packagist3.5.0OSV
  • kunstmaan/media-bundle, Packagist3.5.1OSV
  • kunstmaan/media-bundle, Packagist3.5.2OSV
  • kunstmaan/media-bundle, Packagist3.6.0OSV
  • kunstmaan/media-bundle, Packagist3.6.1OSV
  • kunstmaan/media-bundle, Packagist3.6.2OSV
  • kunstmaan/media-bundle, Packagist3.6.3OSV
  • kunstmaan/media-bundle, Packagist4.0.0OSV
  • kunstmaan/media-bundle, Packagist4.0.0-RC1OSV
  • kunstmaan/media-bundle, Packagist4.0.1OSV
  • kunstmaan/media-bundle, Packagist4.0.2OSV
  • kunstmaan/media-bundle, Packagist4.0.3OSV
  • kunstmaan/media-bundle, Packagist4.1.0OSV
  • kunstmaan/media-bundle, Packagist4.1.1OSV
  • kunstmaan/media-bundle, Packagist4.1.2OSV
  • kunstmaan/media-bundle, Packagist4.1.3OSV
  • kunstmaan/media-bundle, Packagist4.1.4OSV
  • kunstmaan/media-bundle, Packagist4.2.0OSV
  • kunstmaan/media-bundle, Packagist4.2.1OSV
  • kunstmaan/media-bundle, Packagist4.2.2OSV
  • kunstmaan/media-bundle, Packagist4.2.3OSV
  • kunstmaan/media-bundle, Packagist5.0.0OSV
  • kunstmaan/media-bundle, Packagist5.0.0-RC1OSV
  • kunstmaan/media-bundle, Packagist5.0.0-RC2OSV
  • kunstmaan/bundles-cms, Packagistfrom first release, fixed in 7.3.2OSV
  • kunstmaan/bundles-cms, Packagist3.0.0OSV
  • kunstmaan/bundles-cms, Packagist3.0.1OSV
  • kunstmaan/bundles-cms, Packagist3.0.2OSV
  • kunstmaan/bundles-cms, Packagist3.0.3OSV
  • kunstmaan/bundles-cms, Packagist3.1.0OSV
  • kunstmaan/bundles-cms, Packagist3.1.1OSV
  • kunstmaan/bundles-cms, Packagist3.1.2OSV
  • kunstmaan/bundles-cms, Packagist3.1.3OSV
  • kunstmaan/bundles-cms, Packagist3.1.4OSV
  • kunstmaan/bundles-cms, Packagist3.2.0OSV
  • kunstmaan/bundles-cms, Packagist3.2.1OSV
  • kunstmaan/bundles-cms, Packagist3.2.1.1OSV
  • kunstmaan/bundles-cms, Packagist3.2.2OSV
  • kunstmaan/bundles-cms, Packagist3.2.3OSV
  • kunstmaan/bundles-cms, Packagist3.2.4OSV
  • kunstmaan/bundles-cms, Packagist3.2.4.1OSV
  • kunstmaan/bundles-cms, Packagist3.2.5OSV
  • kunstmaan/bundles-cms, Packagist3.2.6OSV
  • kunstmaan/bundles-cms, Packagist3.3.0OSV
  • kunstmaan/bundles-cms, Packagist3.3.1OSV
  • kunstmaan/bundles-cms, Packagist3.3.2OSV
  • kunstmaan/bundles-cms, Packagist3.3.3OSV
  • kunstmaan/bundles-cms, Packagist3.3.4OSV
  • kunstmaan/bundles-cms, Packagist3.4.0OSV
  • kunstmaan/bundles-cms, Packagist3.4.1OSV
  • kunstmaan/bundles-cms, Packagist3.4.2OSV
  • kunstmaan/bundles-cms, Packagist3.5.0OSV
  • kunstmaan/bundles-cms, Packagist3.5.1OSV
  • kunstmaan/bundles-cms, Packagist3.5.2OSV
  • kunstmaan/bundles-cms, Packagist3.6.0OSV
  • kunstmaan/bundles-cms, Packagist3.6.1OSV
  • kunstmaan/bundles-cms, Packagist3.6.2OSV
  • kunstmaan/bundles-cms, Packagist3.6.3OSV
  • kunstmaan/bundles-cms, Packagist4.0.0OSV
  • kunstmaan/bundles-cms, Packagist4.0.0-RC1OSV
  • kunstmaan/bundles-cms, Packagist4.0.1OSV
  • kunstmaan/bundles-cms, Packagist4.0.2OSV
  • kunstmaan/bundles-cms, Packagist4.0.3OSV
  • kunstmaan/bundles-cms, Packagist4.1.0OSV
  • kunstmaan/bundles-cms, Packagist4.1.1OSV
  • kunstmaan/bundles-cms, Packagist4.1.2OSV
  • kunstmaan/bundles-cms, Packagist4.1.3OSV
  • kunstmaan/bundles-cms, Packagist4.1.4OSV
  • kunstmaan/bundles-cms, Packagist4.2.0OSV
  • kunstmaan/bundles-cms, Packagist4.2.1OSV
  • kunstmaan/bundles-cms, Packagist4.2.2OSV
  • kunstmaan/bundles-cms, Packagist4.2.3OSV
  • kunstmaan/bundles-cms, Packagist5.0.0OSV
  • kunstmaan/bundles-cms, Packagist5.0.0-RC1OSV
  • kunstmaan/bundles-cms, Packagist5.0.0-RC2OSV

References 5