A flaw in Node.js Permission Model filesystem enforcement can grant access to paths that do not match a wildcard --allow-fs-read or --allow-fs-write rule.
When the requested path is shorter than the prefix of a wildcard grant, the radix tree lookup stops comparing early and treats the path as a match. For example, --allow-fs-read=/etc/passwd.* also allows reading /etc/passwd. This requires the wildcard grant to sit directly under the root of the permission tree, for example when it is the only grant for that scope. This is a different root cause from CVE-2026-58043.
This vulnerability affects Node.js 26.x.
Weakness
The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.
Extended Description
Access control involves the use of several protection mechanisms such as:
When any mechanism is not applied or otherwise fails, attackers can compromise the security of the product by gaining privileges, reading sensitive information, executing commands, evading detection, etc. There are two distinct behaviors that can introduce access control weaknesses:
Potential Mitigations
- Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
- Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/19.html
- https://cwe.mitre.org/data/definitions/441.html
- https://cwe.mitre.org/data/definitions/478.html
- https://cwe.mitre.org/data/definitions/479.html
- https://cwe.mitre.org/data/definitions/502.html
- https://cwe.mitre.org/data/definitions/503.html
- https://cwe.mitre.org/data/definitions/536.html
- https://cwe.mitre.org/data/definitions/546.html
- https://cwe.mitre.org/data/definitions/550.html
- https://cwe.mitre.org/data/definitions/551.html
- https://cwe.mitre.org/data/definitions/552.html
- https://cwe.mitre.org/data/definitions/556.html
- https://cwe.mitre.org/data/definitions/558.html
- https://cwe.mitre.org/data/definitions/562.html
- https://cwe.mitre.org/data/definitions/563.html
- https://cwe.mitre.org/data/definitions/564.html
- https://cwe.mitre.org/data/definitions/578.html