Craft is a platform for creating digital experiences. Versions 5.0.0-RC1 through 5.8.20 and 4.0.0-RC1 through 4.16.16 are vulnerable to potential authenticated Remote Code Execution via malicious attached Behavior. Note that attackers must have administrator access to the Craft Control Panel for this to work. Users should update to the patched versions (5.8.21 and 4.16.17) to mitigate the issue.
Weakness
The product uses external input with reflection to select which classes or code to use, but it does not sufficiently prevent the input from selecting improper classes or code.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Craft_cms | Craftcms | 4.0.0.1 (including) | 4.16.17 (excluding) |
| Craft_cms | Craftcms | 5.0.1 (including) | 5.8.21 (excluding) |
| Craft_cms | Craftcms | 4.0.0 (including) | 4.0.0 (including) |
| Craft_cms | Craftcms | 4.0.0-rc1 (including) | 4.0.0-rc1 (including) |
| Craft_cms | Craftcms | 4.0.0-rc2 (including) | 4.0.0-rc2 (including) |
| Craft_cms | Craftcms | 4.0.0-rc3 (including) | 4.0.0-rc3 (including) |
| Craft_cms | Craftcms | 5.0.0 (including) | 5.0.0 (including) |
| Craft_cms | Craftcms | 5.0.0-rc1 (including) | 5.0.0-rc1 (including) |
Potential Mitigations
Related Attack Patterns
References
- https://github.com/craftcms/cms/blob/5.x/CHANGELOG.md#5821---2025-12-04
- https://github.com/craftcms/cms/commit/27f55886098b56c00ddc53b69239c9c9192252c7
- https://github.com/craftcms/cms/commit/6e608a1a5bfb36943f94f584b7548ca542a86fef
- https://github.com/craftcms/cms/commit/ec43c497edde0b2bf2e39a119cded2e55f9fe593
- https://github.com/craftcms/cms/security/advisories/GHSA-255j-qw47-wjh5
- https://github.com/craftcms/cms/security/advisories/GHSA-255j-qw47-wjh5