CVE-2026-56394

Description

### Summary An authenticated path traversal in `assets/icon` allows local SVG file read by passing traversal sequences in the `extension` parameter. The issue is caused by file existence checks happening before extension validation. ### Details The endpoint: - `src/controllers/AssetsController.php:1115-1123` - `actionIcon(string $extension)` calls `Assets::iconPath($extension)` and returns `sendFile($path, ...)`. In `Assets::iconPath()`: - Path is built from user-controlled `extension`: - `src/helpers/Assets.php:906-909` - If `file_exists($path)` is true, path is returned immediately: - `src/helpers/Assets.php:910-912` Validation exists in `Assets::iconSvg()`: - `preg_match('/^\w+$/', $extension)` - `src/helpers/Assets.php:927-931` However, that validation is only reached if `iconPath()` does **not** find a file. So traversal payloads that resolve to existing `.svg` files bypass validation and are served by `sendFile()`. ### Impact - Authenticated users can read local .svg files accessible to the application process. ### References - https://github.com/craftcms/cms/commit/30f5f1a8d6edf0f3a00be72c42c78d9dc7d72d5c

How to fix CVE-2026-56394

To remediate CVE-2026-56394, upgrade the affected package to a fixed version below.

• —upgrade to 4.17.7 or later

Is CVE-2026-56394 being exploited?

Low — EPSS is 0.3%, meaning exploitation activity has not been observed at scale.

Affected packages (1)

• >= 4.0.0-RC1, < 4.17.7

CVSS scores

References (3)

• PATCHgithub.com/craftcms/cms
• WEBgithub.com/craftcms/cms/commit/30f5f1a8d6edf0f3a00be72c42c78d9dc7d72d5c
• WEBgithub.com/craftcms/cms/security/advisories/GHSA-c43v-4cr8-6mvp