Summary
Payload contains a path traversal vulnerability in local upload cleanup handling. An authenticated user who can update or delete locally stored uploads may cause cleanup operations to affect files outside the configured upload directory, potentially resulting in data loss or service disruption.
Payload contains a path traversal vulnerability in local upload cleanup handling. An authenticated user who can update or delete locally stored uploads may cause cleanup operations to affect files outside the configured upload directory, potentially resulting in data loss or service disruption.
Affected context
The issue occurs in Payload deployments that store uploads locally and allow authenticated users to manage those uploads. Risk is higher when upload-management permissions are broadly granted or when cleanup paths are derived from user-influenced metadata without sufficiently constraining them to the configured upload directory.
The issue occurs in Payload deployments that store uploads locally and allow authenticated users to manage those uploads. Risk is higher when upload-management permissions are broadly granted or when cleanup paths are derived from user-influenced metadata without sufficiently constraining them to the configured upload directory.
Exploit preconditions
- Attack surface: Local file cleanup performed by the CMS upload-management functionality
- Required access: An authenticated account with permission to update or delete locally stored uploads
- Trigger point: File cleanup after an upload update or deletion operation
- Why exploitation is possible: Cleanup path handling may permit a derived file path to resolve outside the intended upload directory
- Attack surface: Local file cleanup performed by the CMS upload-management functionality
- Required access: An authenticated account with permission to update or delete locally stored uploads
- Trigger point: File cleanup after an upload update or deletion operation
- Why exploitation is possible: Cleanup path handling may permit a derived file path to resolve outside the intended upload directory
Why this happens
The underlying bug is improper validation and containment of file paths used during upload cleanup.
When application-controlled and user-influenced path components are combined without canonicalization and directory-boundary checks, a path may escape the configured storage location. This maps primarily to CWE-22: Improper Limitation of a Pathname to a Restricted Directory, with a related connection to CWE-73: External Control of File Name or Path.
The underlying bug is improper validation and containment of file paths used during upload cleanup.
When application-controlled and user-influenced path components are combined without canonicalization and directory-boundary checks, a path may escape the configured storage location. This maps primarily to CWE-22: Improper Limitation of a Pathname to a Restricted Directory, with a related connection to CWE-73: External Control of File Name or Path.
Potential impact
- Attackers may delete files outside the configured upload directory
- Application data or operational files could be lost
- The service may become unavailable or unstable
- Cleanup operations could disrupt related components sharing the same filesystem
- Integrity and availability of hosted content may be affected
- Attackers may delete files outside the configured upload directory
- Application data or operational files could be lost
- The service may become unavailable or unstable
- Cleanup operations could disrupt related components sharing the same filesystem
- Integrity and availability of hosted content may be affected
General mitigation guidance
Mitigation generally focuses on enforcing storage boundaries for every file operation and reducing trust in path-related input.
Defensive patterns include:
- Resolve candidate paths canonically and verify that they remain beneath the intended upload directory
- Prefer opaque storage identifiers and server-controlled metadata over user-provided file paths
- Reject absolute paths, traversal components, symbolic-link escapes, and ambiguous path encodings
- Apply the same containment checks to update, delete, rename, and cleanup workflows
- Restrict upload-management permissions according to least privilege
- Use dedicated storage locations and filesystem permissions that limit the impact of an unintended deletion
- Preserve backups and recovery controls for locally stored content
Mitigation generally focuses on enforcing storage boundaries for every file operation and reducing trust in path-related input.
Defensive patterns include:
- Resolve candidate paths canonically and verify that they remain beneath the intended upload directory
- Prefer opaque storage identifiers and server-controlled metadata over user-provided file paths
- Reject absolute paths, traversal components, symbolic-link escapes, and ambiguous path encodings
- Apply the same containment checks to update, delete, rename, and cleanup workflows
- Restrict upload-management permissions according to least privilege
- Use dedicated storage locations and filesystem permissions that limit the impact of an unintended deletion
- Preserve backups and recovery controls for locally stored content
How teams detect issues like this
Organizations can look for this class of issue through:
- Static analysis rules identifying path construction from request data or upload metadata
- Code review checks for canonicalization followed by directory-boundary validation
- Tests that exercise relative paths, absolute paths, encoded separators, symbolic links, and nested cleanup targets
- Runtime monitoring for deletion events outside approved upload roots
- Policy enforcement requiring dedicated upload storage and least-privilege file permissions
- Automated security review tools that flag unsafe file path handling and external control of filenames
Organizations can look for this class of issue through:
- Static analysis rules identifying path construction from request data or upload metadata
- Code review checks for canonicalization followed by directory-boundary validation
- Tests that exercise relative paths, absolute paths, encoded separators, symbolic links, and nested cleanup targets
- Runtime monitoring for deletion events outside approved upload roots
- Policy enforcement requiring dedicated upload storage and least-privilege file permissions
- Automated security review tools that flag unsafe file path handling and external control of filenames
