Node: Improper Limitation of a Pathname to a Restricted Directory
CVE-2023-39332 is a critical-severity improper limitation of a pathname to a restricted directory vulnerability in Node from Node.js, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 4.*, 5.*, 6.* as the first without the flaw, so updating Node to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 2.19% chance of exploitation within 30 days, higher than 83% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Node to 4.* or 5.* or 6.* or 7.*, whichever matches your release line, or a later version.
- Update Node.js to 20.8.0 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Node.js | Node | 4.0 up to, but not including, 4.*; 5.0 up to, but not including, 5.*; 6.0 up to, but not including, 6.*; 7.0 up to, but not including, 7.*; 8.0 up to, but not including, 8.*; 9.0 up to, but not including, 9.*; 10.0 up to, but not including, 10.*; 11.0 up to, but not including, 11.*; and 8 more ranges | 4.*, 5.*, 6.*, 7.*, 8.*, 9.* |
| Node.js | Node.js | 20.0.0 up to, but not including, 20.8.0 | 20.8.0 |
| Fedora Project | Fedora | 39 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
Official description
Various `node:fs` functions allow specifying paths as either strings or `Uint8Array` objects. In Node.js environments, the `Buffer` class extends the `Uint8Array` class. Node.js prevents path traversal through strings (see CVE-2023-30584) and `Buffer` objects (see CVE-2023-32004), but not through non-`Buffer` `Uint8Array` objects. This is distinct from CVE-2023-32004 which only referred to `Buffer` objects. However, the vulnerability follows the same pattern using `Uint8Array` instead of `Buffer`. Please note that at the time this CVE was issued, the permission model is an experimental feature of Node.js.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
How developers prevent this class of flaw
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- hackerone.com/reports/2199818Third Party Advisory
- security.netapp.com/advisory/ntap-20231116-0009/Third Party Advisory
Other references
Other vulnerabilities in Node
- 7.5 High severity
- 7.5 High severity
- 8.1 High severity
- 7.5 High severity
- 7.5 High severity
- 8.1 High severity
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 7.1 High severity
- 7.1 High severity
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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