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

> Authenticated users can delete assets in unauthorized volumes by exploiting a permission check flaw during file replacement operations.

- **Severity:** Medium 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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Jul 2026
- **Updated:** 2 Jul 2026
- **Also known as:** GHSA-qh45-9g5p-m2v4

## What is CVE-2026-50283?

CVE-2026-50283 is a medium-severity missing authorization vulnerability in craftcms cms, published on 1 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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.

Weakness: CWE-862 (Missing Authorization), CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-50283?

4 open source packages ship an affected version, including craftcms/cms.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `craftcms/cms` | Packagist | From 4.0.0-RC1 | 4.17.14 |
| `craftcms/cms` | Packagist | From 4.0.0-RC1 | 4.17.14 |
| `craftcms/cms` | Packagist | From 5.0.0-RC1 | 5.9.21 |
| `craftcms/cms` | Packagist | From 5.0.0-RC1 | 5.9.21 |

## How do I fix CVE-2026-50283?

Upgrade craftcms/cms to a fixed version for your release line: 4.17.14 or 5.9.21.

## Is CVE-2026-50283 being exploited?

There is no known exploitation of CVE-2026-50283 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-50283 and fix it if it is affected.

What it is: CVE-2026-50283 is a medium-severity missing authorization vulnerability in craftcms cms, published on 1 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-50283 in the wild and no public exploit code.

Affected packages and fixed versions:
- craftcms/cms (Packagist): affected from 4.0.0-RC1; fixed in 4.17.14
- craftcms/cms (Packagist): affected from 4.0.0-RC1; fixed in 4.17.14
- craftcms/cms (Packagist): affected from 5.0.0-RC1; fixed in 5.9.21
- craftcms/cms (Packagist): affected from 5.0.0-RC1; fixed in 5.9.21

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-50283/ (Markdown: https://insights.sbomify.com/CVE-2026-50283/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-50283
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-50283
- OSV: https://osv.dev/vulnerability/CVE-2026-50283

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-50283/
Summaries are generated and may contain mistakes; the official description above is the record.