webpack-dev-middleware: Improper Limitation of a Pathname to a Restricted Directory
CVE-2026-76844 is a high-severity improper limitation of a pathname to a restricted directory vulnerability in webpack-dev-middleware from Webpack, with a CVSS 3.1 base score of 7.4 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists versions 7.4.6, 8.3.0 as the first without the flaw, so updating webpack-dev-middleware to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.68% chance of exploitation within 30 days, higher than 53% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update webpack-dev-middleware to 7.4.6 or 8.3.0, whichever matches your release line, or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Webpack | webpack-dev-middleware | 5.3.4 and earlier; 6.1.2 through 6.1.3; 7.1.0 up to, but not including, 7.4.6; 8.0.0 up to, but not including, 8.3.0 | 7.4.6, 8.3.0 |
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
- RequiredA user must take an action such as opening a file or link.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.3 | High | CNA (vulncheck.com) |
| CVSS 3.1 | 7.4 | High | CNA (vulncheck.com) |
Official description
webpack-dev-middleware 5.3.4, 6.1.2 through 6.1.3, 7.1.0 before 7.4.6, and 8.0.0 before 8.3.0 contains a path traversal vulnerability in getFilenameFromUrl that bypasses the fix for CVE-2024-29180: a publicPath without a trailing slash is matched by string prefix, and the '..' guard runs before that prefix is stripped. Unauthenticated attackers can request a path such as /assets../secret to read files one directory above the output directory when the middleware serves from the physical filesystem through writeToDisk or a custom outputFileSystem.
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: poc, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
- github.com/webpack/webpack-dev-middleware/commit/13344e78b26d88fe9b7c8381a3860e248a52359b
- github.com/webpack/webpack-dev-middleware/commit/cefccbac330c29052fc6dffe85fd292ea2ac782b
- github.com/webpack/webpack-dev-middleware/releases/tag/v7.4.6
- github.com/webpack/webpack-dev-middleware/releases/tag/v8.3.0
Other references
Other vulnerabilities in webpack-dev-middleware
- 7.5 High severity
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 7.2 High severity
- 8.2 High severity
- 8.2 High severity
- 7.5 High severity
- 9.9 Critical severity
- 8.8 High severity
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