CVE-2025-59364: Express xss sanitizer Cross-Site Scripting Vulnerability

Q: What is CVE-2025-59364?

CVE-2025-59364 is a security vulnerability in Express xss sanitizer involving express-xss-sanitizer has an unbounded recursion depth under CWE-674: Uncontrolled Recursion.

Q: Which Express xss sanitizer versions are affected?

Affected versions include releases prior to 2.0.1 across affected packages: express-xss-sanitizer.

Q: What version fixes CVE-2025-59364?

Upgrading to 2.0.1 (or the latest patched release for your respective branch) resolves the vulnerability.

Q: Is express-xss-sanitizer affected?

Yes, express-xss-sanitizer is affected in releases prior to 2.0.1. Upgrade your dependency to 2.0.1 or later.

Q: What CWE is associated with CVE-2025-59364?

CVE-2025-59364 is classified under CWE-674: Uncontrolled Recursion (The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.).

Q: How can I check npm dependencies for CVE-2025-59364?

Run the dependency tree command: 'npm ls express-xss-sanitizer'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.

MODERATE

Advisory Identifier: GHSA-hvq2-wf92-j4f3

CWE-674

Published 2025-09-26

Advisory Summary

CVE-2025-59364 is a MODERATE cross-site scripting vulnerability (CWE-674: Uncontrolled Recursion) affecting Express xss sanitizer libraries in the npm ecosystem. The issue involves express-xss-sanitizer has an unbounded recursion depth. Remediation is available by upgrading affected packages to version 2.0.1.

CVE-2025-59364 at a Glance

CVE Identifier CVE-2025-59364

GHSA Identifier GHSA-hvq2-wf92-j4f3

Severity MODERATE

CVSS v3.1 Base Score N/A

CWE Classification CWE-674: Uncontrolled Recursion

Affected Product Express xss sanitizer

Package Ecosystem npm

Published Date 2025-09-26

Last Updated 2025-09-26

How to Fix CVE-2025-59364

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

express-xss-sanitizer fixed: 2.0.1

npm install express-xss-sanitizer@2.0.1

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 express-xss-sanitizer

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2025-59364, inspect your project dependencies using npm:

npm ls express-xss-sanitizer

Analyze the terminal output to locate any version of Express xss sanitizer in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.0.1), your application is affected.

Note: The npm ls express-xss-sanitizer 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-674: Uncontrolled Recursion, where the product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack. In Express xss sanitizer, 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

# Security Advisory: express-xss-sanitizer ## Overview A vulnerability was discovered in express-xss-sanitizer that allowed unbounded recursion depth during sanitization of nested objects. ## Affected Versions - All versions prior to 2.0.1 ## Patched Versions - 2.0.1 and later ## Description The sanitize function in lib/sanitize.js performed recursive sanitization without depth limiting, making it vulnerable to stack overflow attacks via specially crafted deeply nested JSON objects. ## Impact An attacker could cause denial-of-service by sending a request with deeply nested structures, potentially crashing the Node.js process. ## Solution Upgrade to version 2.0.1 or later: ```bash npm install express-xss-sanitizer@latest ```

CVE-2025-59364 Affected Express xss sanitizer Versions

1 component(s)

Fixed Versions:

2.0.1

Product / Package	Ecosystem	Affected Versions	Fixed Version
express-xss-sanitizer npm/express-xss-sanitizer	npm	< 2.0.1	2.0.1

References

GitHub Advisory / Wiki ADVISORY

https://github.com/AhmedAdelFahim/express-xss-sanitizer/security/advisories/GHSA-hvq2-wf92-j4f3

NVD — CVE-2025-59364 NVD

https://nvd.nist.gov/vuln/detail/CVE-2025-59364

Express xss sanitizer Source Repository REPOSITORY

https://github.com/AhmedAdelFahim/express-xss-sanitizer/pull/23

Security Fix Commit FIX COMMIT

https://github.com/AhmedAdelFahim/express-xss-sanitizer/commit/62d6542a2a57298da7a2e02de623454007e4f6d6

Express xss sanitizer Security Information SECURITY

https://dbugs.ptsecurity.com/vulnerability/PT-2025-37434

Express xss sanitizer Source Repository REPOSITORY

https://gist.github.com/Spendroslav/177804eaef5acfb222a550de212a1b94

Express xss sanitizer Source Repository REPOSITORY

https://github.com/AhmedAdelFahim/express-xss-sanitizer

www.npmjs.com/package/express-xss... WEB

https://www.npmjs.com/package/express-xss-sanitizer

www.tenable.com/cve/cve-2025-59364 WEB

https://www.tenable.com/cve/CVE-2025-59364

Frequently Asked Questions

What is CVE-2025-59364?

CVE-2025-59364 is a security vulnerability in Express xss sanitizer involving express-xss-sanitizer has an unbounded recursion depth under CWE-674: Uncontrolled Recursion.

Which Express xss sanitizer versions are affected?

Affected versions include releases prior to 2.0.1 across affected packages: express-xss-sanitizer.

What version fixes CVE-2025-59364?

Upgrading to 2.0.1 (or the latest patched release for your respective branch) resolves the vulnerability.

Is express-xss-sanitizer affected?

Yes, express-xss-sanitizer is affected in releases prior to 2.0.1. Upgrade your dependency to 2.0.1 or later.

What CWE is associated with CVE-2025-59364?

CVE-2025-59364 is classified under CWE-674: Uncontrolled Recursion (The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.).

How can I check npm dependencies for CVE-2025-59364?

Run the dependency tree command: 'npm ls express-xss-sanitizer'. 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-hvq2-wf92-j4f3",
  "modified" : "2025-09-26T14:38:14Z",
  "published" : "2025-09-26T14:38:13Z",
  "aliases" : [ "CVE-2025-59364" ],
  "summary" : "express-xss-sanitizer has an unbounded recursion depth",
  "details" : "# Security Advisory: express-xss-sanitizer\n\n## Overview\nA vulnerability was discovered in express-xss-sanitizer that allowed unbounded recursion depth during sanitization of nested objects.\n\n## Affected Versions\n- All versions prior to 2.0.1\n\n## Patched Versions\n- 2.0.1 and later\n\n## Description\nThe sanitize function in lib/sanitize.js performed recursive sanitization without depth limiting, making it vulnerable to stack overflow attacks via specially crafted deeply nested JSON objects.\n\n## Impact\nAn attacker could cause denial-of-service by sending a request with deeply nested structures, potentially crashing the Node.js process.\n\n## Solution\nUpgrade to version 2.0.1 or later:\n\n```bash\nnpm install express-xss-sanitizer@latest\n```",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "express-xss-sanitizer"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.0.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/AhmedAdelFahim/express-xss-sanitizer/security/advisories/GHSA-hvq2-wf92-j4f3"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-59364"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/AhmedAdelFahim/express-xss-sanitizer/pull/23"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/AhmedAdelFahim/express-xss-sanitizer/commit/62d6542a2a57298da7a2e02de623454007e4f6d6"
  }, {
    "type" : "WEB",
    "url" : "https://dbugs.ptsecurity.com/vulnerability/PT-2025-37434"
  }, {
    "type" : "WEB",
    "url" : "https://gist.github.com/Spendroslav/177804eaef5acfb222a550de212a1b94"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/AhmedAdelFahim/express-xss-sanitizer"
  }, {
    "type" : "WEB",
    "url" : "https://www.npmjs.com/package/express-xss-sanitizer"
  }, {
    "type" : "WEB",
    "url" : "https://www.tenable.com/cve/CVE-2025-59364"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-674" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-09-26T14:38:13Z",
    "nvd_published_at" : null
  }
}

CVSS V4

N/A MODERATE

Attack Vector N/A

Attack Complexity N/A

Privileges Required N/A

User Interaction N/A

Scope N/A

Confidentiality N/A

Integrity N/A

Availability N/A

Vector String

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Advisory Metadata

Source ID: GHSA-hvq2-wf92-j4f3
Schema Version: 1.4.0
Published: 2025-09-26 14:38
Last Modified: 2025-09-26 14:38
Database Record File: advisories/github-reviewed/2025/09/GHSA-hvq2-wf92-j4f3/GHSA-hvq2-wf92-j4f3.json