CVE-2025-59364 is a medium-severity (CVSS 5.3) CWE-674 vulnerability in express-xss-sanitizer. A fix is available for express-xss-sanitizer — see the affected versions and patch details below.
express-xss-sanitizer has an unbounded recursion depth
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-59364.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
express-xss-sanitizernpmDescription
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:
npm install express-xss-sanitizer@latest
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | express-xss-sanitizer | all versions | 2.0.1npm install express-xss-sanitizer@2.0.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for express-xss-sanitizer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update express-xss-sanitizer to 2.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-59364 is resolved across your whole dependency graph.
Workarounds
Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.
Frequently Asked Questions
Is CVE-2025-59364 in your dependencies?
Find it across npm, including transitive dependencies.