vulnerability / NVI-00008308 / Revision 5
Kunstmaan CMS: MediaBundle extension blacklist bypass allows authenticated administrators to upload executable PHP files leading to remote code execution
GitHub lists this reviewed advisory for kunstmaan/media-bundle, kunstmaan/bundles-cms. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
7.2 high
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
0.416%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.35967. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
kunstmaan/media-bundle
source listed< 7.3.2
### 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
kunstmaan/bundles-cms
source listed< 7.3.2
### 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
kunstmaan/media-bundle
source listedECOSYSTEM: introduced 0; fixed 7.3.2
### 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
kunstmaan/bundles-cms
source listedECOSYSTEM: introduced 0; fixed 7.3.2
### 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
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
- vendor patch
The original advisory lists fixed boundaries 7.3.2 for kunstmaan/media-bundle. Confirm the publisher’s latest guidance.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database via OSV
- vendor patch
The original advisory lists fixed boundaries 7.3.2 for kunstmaan/bundles-cms. Confirm the publisher’s latest guidance.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database via OSV
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-p279-5wcv-45vq ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- GHSA-p279-5wcv-45vq ↗
GitHub Advisory Database via OSV · vendor advisory
Observed . GitHub-origin advisory, CC-BY-4.0; OSV is an aggregate copy, not independent corroboration.
- CVE-2026-104890 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 5 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 4 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 3 ·
Source facts changed; compare the preserved prior revision.
- Revision 2 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.