Craft CMS: Unauthorized Deletion of Source Assets During File Replacement

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

5.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-50283: 0.36% estimated exploitation activity in the next 30 days; percentile 30.33 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

We have identified an authorization issue in Craft CMS AssetsController::actionReplaceFile that can delete a source asset without source delete permission by supplying both assetId and sourceAssetId. Description Craft CMS’s craft\\controllers\\AssetsController::actionReplaceFile() supports replacing a target asset file using another existing asset as the source. The action loads: - $assetToReplace from assetId - $sourceAsset from sourceAssetId It then enforces replace permissions using ($assetToReplace ?: $sourceAsset). When both IDs are provided, this expression resolves to the target asset so no permission check is performed against the source asset volume. src/controllers/AssetsController.php:L433-L434 In the branch where both assets are present, Craft copies the source file into the target and then deletes the source asset. There is no check for deleteAssets:<sourceVolumeUid or deletePeerAssets:<sourceVolumeUid for the source asset before deletion.…

Published by the source

2 Jul 2026, 18:48 UTC

Last modified by the source

2 Jul 2026, 18:48 UTC

Source last checked

26 Oct 2026, 14:49 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-qh45-9g5p-m2v4

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# Patch Next advisory brief: CVE-2026-50283

Advisory: Craft CMS: Unauthorized Deletion of Source Assets During File Replacement
IDs: CVE-2026-50283, GHSA-qh45-9g5p-m2v4
Record: https://patchnext.com/advisories/cve-2026-50283 (revision 1, source checked 26 Oct 2026, 14:49 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: craftcms/cms 5.9.21, 4.17.14. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist craftcms/cms: affected >= 5.0.0-RC1, < 5.9.21; >= 4.0.0-RC1, < 4.17.14; fixed in 4.17.14, 5.9.21

## Suggested inspection (read-only)
- Packagist craftcms/cms: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on craftcms/cms.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-qh45-9g5p-m2v4 (GitHub-reviewed advisory GHSA-qh45-9g5p-m2v4 lists affected ranges: Packagist craftcms/cms >=5.0.0-RC1 =4.0.0-RC1 <4.17.14)

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