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CVE-2026-21637

A flaw in Node.js TLS error handling allows remote attackers to crash or exhaust resources of a TLS server when `pskCallback` or `ALPNCallba

Published
Last modified
published
Not listed in CISA KEV
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: yes
  • Technical impact: partial

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: yes · Technical impact: partial

  3. Record last updated

Affected versions

  • nodejs node

    From 20.19.6 · through 20.19.6; From 22.21.1 · through 22.21.1; From 24.12.0 · through 24.12.0; From 25.2.1 · through 25.2.1; From 4.0; From 5.0; From 6.0; From 7.0; From 8.0; From 9.0; From 10.0; From 11.0; From 12.0; From 13.0; From 14.0; From 15.0; From 16.0; From 17.0; From 18.0

References 1

nodejs.org