CVE-2025-59364Network attack vector

Denial of service via unbounded sanitization recursion

Published Sep 14, 2025 · Updated Sep 14, 2025

Uncontrolled recursion in express-xss-sanitizer before 2.0.1 allows remote attackers to crash a Node.js process with deeply nested JSON. The sanitize function in lib/sanitize.js recursively traverses nested arrays and objects without enforcing a depth limit, exhausting the JavaScript call stack. An endpoint must parse attacker-supplied JSON and pass it through the middleware or sanitize API; successful exploitation interrupts only that Node.js service.

CVSS severity5.3
Medium
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled recursion in express-xss-sanitizer before 2.0.1 allows remote attackers to crash a Node.js process with deeply nested JSON. The sanitize function in lib/sanitize.js recursively traverses nested arrays and objects without enforcing a depth limit, exhausting the JavaScript call stack. An endpoint must parse attacker-supplied JSON and pass it through the middleware or sanitize API; successful exploitation interrupts only that Node.js service.

The record

CVE
CVE-2025-59364
Published
Sep 14, 2025
Updated
Sep 14, 2025
Vendor
Express XSS Sanitizer project
Product
express-xss-sanitizer
Classifications
CWE-674, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 14, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Express XSS Sanitizer project · express-xss-sanitizerversion=2.0.0

Published CVSS scores

6.9GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
5.3MITRECVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-674Uncontrolled Recursion
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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