CVE-2026-21637
7.5 · HIGHOverview
CVE-2026-21637 is a high-severity vulnerability affecting nodejs node.js. It was published on January 20, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
A flaw in Node.js TLS error handling allows remote attackers to crash or exhaust resources of a TLS server when `pskCallback` or `ALPNCallback` are in use. Synchronous exceptions thrown during these callbacks bypass standard TLS error handling paths (tlsClientError and error), causing either immediate process termination or silent file descriptor leaks that eventually lead to denial of service. Because these callbacks process attacker-controlled input during the TLS handshake, a remote client can repeatedly trigger the issue. This vulnerability affects TLS servers using PSK or ALPN callbacks across Node.js versions where these callbacks throw without being safely wrapped.
Remediation
Check the references section for vendor advisories and patches from nodejs. Update node.js to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| nodejs | node.js | >= 4.0.0, < 20.20.0 | Affected |
Frequently Asked Questions
What is CVE-2026-21637?
CVE-2026-21637 is a high-severity vulnerability affecting nodejs node.js. It was published on January 20, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
How severe is CVE-2026-21637?
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-21637?
Check the references section for vendor advisories and patches from nodejs. Update node.js to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-21637?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-21637 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
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