CVE-2026-21637
Published: Jan 20, 2026
Modified: Jan 21, 2026
CVSS v3.0
5.9
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.
| Vendor | Product | Versions |
|---|---|---|
nodejs | node | affected 20.19.6 - <= 20.19.6affected 22.21.1 - <= 22.21.1affected 24.12.0 - <= 24.12.0affected 25.2.1 - <= 25.2.1affected 4.0 - < 4.*+14 more versions |
CVSS v3.0 Details
CVSS v3.0 Vector
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
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