Summary
A path traversal vulnerability in Backstage's Confluence-to-Markdown scaffolder backend module can allow generated content to be written outside the intended task workspace. An authenticated user who can run an affected template and control its repository file location may overwrite files in locations writable by the Backstage backend process.
A path traversal vulnerability in Backstage's Confluence-to-Markdown scaffolder backend module can allow generated content to be written outside the intended task workspace. An authenticated user who can run an affected template and control its repository file location may overwrite files in locations writable by the Backstage backend process.
Affected context
The issue occurs in Backstage deployments using the affected Confluence-to-Markdown scaffolder backend module when repository file locations are derived from user-controlled template input without sufficient path containment checks. Risk depends on whether an authenticated user can execute the relevant template and whether the backend process has write access to sensitive locations outside the task workspace.
The issue occurs in Backstage deployments using the affected Confluence-to-Markdown scaffolder backend module when repository file locations are derived from user-controlled template input without sufficient path containment checks. Risk depends on whether an authenticated user can execute the relevant template and whether the backend process has write access to sensitive locations outside the task workspace.
Exploit preconditions
- Attack surface: Backstage scaffolder backend template execution
- Required access: Authentication and permission to execute an affected template
- Required control: Ability to influence the repository file location used by the module
- Trigger point: Generation of Confluence-derived Markdown content
- Why exploitation is possible: The destination path may escape the intended workspace and resolve to another backend-writable location
- Attack surface: Backstage scaffolder backend template execution
- Required access: Authentication and permission to execute an affected template
- Required control: Ability to influence the repository file location used by the module
- Trigger point: Generation of Confluence-derived Markdown content
- Why exploitation is possible: The destination path may escape the intended workspace and resolve to another backend-writable location
Why this happens
The underlying bug is improper validation and containment of a path assembled from repository or template-controlled input. When a component accepts a destination path without reliably normalizing it and confirming that it remains beneath an approved workspace directory, traversal sequences or equivalent path representations may redirect writes elsewhere. This maps to CWE-22: Improper Limitation of a Pathname to a Restricted Directory, commonly known as path traversal.
The underlying bug is improper validation and containment of a path assembled from repository or template-controlled input. When a component accepts a destination path without reliably normalizing it and confirming that it remains beneath an approved workspace directory, traversal sequences or equivalent path representations may redirect writes elsewhere. This maps to CWE-22: Improper Limitation of a Pathname to a Restricted Directory, commonly known as path traversal.
Potential impact
- Sensitive or operational files may be overwritten
- Generated content may be placed in unintended application directories
- Backstage task and repository integrity could be compromised
- The backend process may be exposed to configuration or code changes
- Further compromise could occur if overwritten files are later loaded or executed
- Sensitive or operational files may be overwritten
- Generated content may be placed in unintended application directories
- Backstage task and repository integrity could be compromised
- The backend process may be exposed to configuration or code changes
- Further compromise could occur if overwritten files are later loaded or executed
General mitigation guidance
Mitigation generally focuses on enforcing a strict destination boundary and reducing trust in paths supplied through templates or repository metadata.
Common defensive patterns include:
- Canonicalizing paths before validation and requiring them to remain beneath an approved workspace root
- Rejecting absolute paths, traversal components, and alternate path representations
- Using trusted path-joining utilities with explicit containment checks
- Restricting template authors and execution permissions according to least privilege
- Running the backend with minimal filesystem write permissions
- Separating generated-content directories from configuration, source, and executable locations
Mitigation generally focuses on enforcing a strict destination boundary and reducing trust in paths supplied through templates or repository metadata.
Common defensive patterns include:
- Canonicalizing paths before validation and requiring them to remain beneath an approved workspace root
- Rejecting absolute paths, traversal components, and alternate path representations
- Using trusted path-joining utilities with explicit containment checks
- Restricting template authors and execution permissions according to least privilege
- Running the backend with minimal filesystem write permissions
- Separating generated-content directories from configuration, source, and executable locations
How teams detect issues like this
Organizations can look for path traversal risks through:
- Static analysis rules for path joins involving template, repository, or request-controlled values
- Code review checks requiring canonicalization and workspace-boundary enforcement
- Tests covering absolute paths, traversal sequences, encoded separators, symlinks, and platform-specific path forms
- Runtime monitoring for writes outside approved scaffolder workspace directories
- Policy enforcement that limits backend filesystem permissions and template execution capabilities
Automated code review and software composition analysis tools may help identify related unsafe path-handling patterns.
Organizations can look for path traversal risks through:
- Static analysis rules for path joins involving template, repository, or request-controlled values
- Code review checks requiring canonicalization and workspace-boundary enforcement
- Tests covering absolute paths, traversal sequences, encoded separators, symlinks, and platform-specific path forms
- Runtime monitoring for writes outside approved scaffolder workspace directories
- Policy enforcement that limits backend filesystem permissions and template execution capabilities
Automated code review and software composition analysis tools may help identify related unsafe path-handling patterns.
