In Eclipse Theia versions 0.7.0 and up until including 1.73.1, the PreferenceUtils.merge function in @theia/core recursively merges preference values without rejecting prototype-related keys (__proto__, constructor, prototype). Because this function is invoked by PreferenceServiceImpl.doResolve for every preference resolution across scopes (default, user, workspace, folder), a crafted preference value in a workspace settings file (.theia/settings.json or .vscode/settings.json) can pollute Object.prototype when the user opens the workspace, potentially altering application logic across the Theia process.
Weakness
The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.
Potential Mitigations
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/1.html
- https://cwe.mitre.org/data/definitions/180.html
- https://cwe.mitre.org/data/definitions/77.html