Craft CMS: GraphQL Asset Mutation Privilege Escalation

There is a Privilege Escalation vulnerability in Craft CMS’s GraphQL API that allows an authenticated user with write access to one asset volume to escalate their privileges and modify/transfer assets belonging to any other volume, including restricted or private volumes to which they should not have access.

Summary:

Type: Privilege Escalation (CWE-269) Affected: Craft CMS 5.x (likely affects 4.x and 3.x as well) Location: src/gql/resolvers/mutations/Asset.php lines 57-107

Root Cause:

The saveAsset GraphQL mutation validates authorization against the schema-resolved volume but fetches the target asset by ID without verifying that the asset belongs to the authorized volume. This allows unauthorized cross-volume asset modification and transfer.

Impact:

• Transfer confidential assets from private volumes to public volumes (data exfiltration)
• Modify asset metadata in restricted volumes
• Bypass multi-tenant isolation in shared hosting environments