CVE-2026-17495: Moment Path Traversal Vulnerability

MODERATE
Advisory Identifier: GHSA-4p3w-j4w9-5jqw
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CVSS 5.9
CWE-27
Published
Advisory Summary

CVE-2026-17495 is a MODERATE (CVSS 5.9) path traversal vulnerability (CWE-27: Path Traversal: 'dir/../../filename') affecting Moment libraries in the npm ecosystem. The issue involves moment vulnerable to path traversal via crafted non-string locale name. Remediation is available by upgrading affected packages to version 2.31.0.

CVE-2026-17495 at a Glance

CVE Identifier CVE-2026-17495
GHSA Identifier GHSA-4p3w-j4w9-5jqw
Severity MODERATE
CVSS v3.1 Base Score 5.9
CWE Classification CWE-27: Path Traversal: 'dir/../../filename'
Affected Product Moment
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 5.9

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-17495

To remediate this vulnerability, upgrade all affected Moment dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

moment fixed: 2.31.0 
npm install moment@2.31.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls moment

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-17495, inspect your project dependencies using npm:

npm ls moment

Analyze the terminal output to locate any version of Moment in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.31.0), your application is affected.

Note: The npm ls moment command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-27: Path Traversal: 'dir/../../filename', where the product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize multiple internal "../" sequences that can resolve to a location that is outside of that directory. In Moment, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact moment before 2.31.0 is vulnerable to path traversal in `moment.locale()`. When an application passes a non-string, attacker-influenced value to `moment.locale()`, a specially crafted object can bypass the locale name validation and cause moment to load a file from an attacker-controlled path. This is a further bypass of the validation added in 2.29.2 for [CVE-2022-24785](https://github.com/moment/moment/security/advisories/GHSA-8hfj-j24r-96c4). This affects server-side (npm) users only. Plain string input is not affected: the existing validation correctly rejects strings that contain path separators. ### Patches This issue is patched in moment 2.31.0. ### Workarounds Validate that any user-supplied input is a string before passing it to `moment.locale()`.

CVE-2026-17495 Affected Moment Versions

1 component(s)
Fixed Versions:
2.31.0
Product / Package Ecosystem Affected Versions Fixed Version
moment
npm/moment
npm
≥ 2.29.2
< 2.31.0
2.31.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/moment/moment/security/advisories/GHSA-4p3w-j4w9-5jqw
NVD — CVE-2026-17495 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-17495
Moment Source Repository REPOSITORY
https://github.com/moment/moment/pull/6386
Security Fix Commit FIX COMMIT
https://github.com/moment/moment/commit/5f7d983c9881e65e07574de9dda3190d99520c07
Moment Security Information SECURITY
https://cna.openjsf.org/security-advisories.html
Moment Source Repository REPOSITORY
https://github.com/moment/moment
Moment Release RELEASE
https://github.com/moment/moment/releases/tag/2.31.0

Frequently Asked Questions

What is CVE-2026-17495?
CVE-2026-17495 is a security vulnerability in Moment involving moment vulnerable to Path Traversal via crafted non-string locale name under CWE-27: Path Traversal: 'dir/../../filename'.
Which Moment versions are affected?
Affected versions include releases prior to 2.31.0 across affected packages: moment.
What version fixes CVE-2026-17495?
Upgrading to 2.31.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is moment affected?
Yes, moment is affected in releases prior to 2.31.0. Upgrade your dependency to 2.31.0 or later.
What is the CVSS score of CVE-2026-17495?
CVE-2026-17495 has a CVSS v3.1 base score of 5.9 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N.
What CWE is associated with CVE-2026-17495?
CVE-2026-17495 is classified under CWE-27: Path Traversal: 'dir/../../filename' (The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize multiple internal "../" sequences that can resolve to a location that is outside of that directory.).
How can I check npm dependencies for CVE-2026-17495?
Run the dependency tree command: 'npm ls moment'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-4p3w-j4w9-5jqw",
  "modified" : "2026-09-29T23:46:02Z",
  "published" : "2026-09-29T23:46:02Z",
  "aliases" : [ "CVE-2026-17495" ],
  "summary" : "moment vulnerable to Path Traversal via crafted non-string locale name",
  "details" : "### Impact\n\nmoment before 2.31.0 is vulnerable to path traversal in `moment.locale()`. When an application passes a non-string, attacker-influenced value to `moment.locale()`, a specially crafted object can bypass the locale name validation and cause moment to load a file from an attacker-controlled path. This is a further bypass of the validation added in 2.29.2 for [CVE-2022-24785](https://github.com/moment/moment/security/advisories/GHSA-8hfj-j24r-96c4).\n\nThis affects server-side (npm) users only. Plain string input is not affected: the existing validation correctly rejects strings that contain path separators.\n\n### Patches\n\nThis issue is patched in moment 2.31.0.\n\n### Workarounds\n\nValidate that any user-supplied input is a string before passing it to `moment.locale()`.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "moment"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.29.2"
      }, {
        "fixed" : "2.31.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/moment/moment/security/advisories/GHSA-4p3w-j4w9-5jqw"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-17495"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/moment/moment/pull/6386"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/moment/moment/commit/5f7d983c9881e65e07574de9dda3190d99520c07"
  }, {
    "type" : "WEB",
    "url" : "https://cna.openjsf.org/security-advisories.html"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/moment/moment"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/moment/moment/releases/tag/2.31.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-27" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-29T23:46:02Z",
    "nvd_published_at" : "2026-09-15T06:16:57Z"
  }
}