5.9
Medium
CVE-2026-21637 A flaw in Node.js TLS error handling allows remote attackers to crash or exhaust resources of a TLS server when…
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.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Node | 25.2.1 | No fix stated |
| Node | 24.12.0 | No fix stated |
| Node | 22.21.1 | No fix stated |
| Node | 20.19.6 | No fix stated |
| Node 18.0 | 18.0 → latest | No fix stated |
| Node 17.0 | 17.0 → latest | No fix stated |
| Node 16.0 | 16.0 → latest | No fix stated |
| Node 15.0 | 15.0 → latest | No fix stated |
| Node 14.0 | 14.0 → latest | No fix stated |
Show the 10 other branches Hide the 10 other branches
| Product | Affected versions | Fixed in |
|---|---|---|
| Node 13.0 | 13.0 → latest | No fix stated |
| Node 12.0 | 12.0 → latest | No fix stated |
| Node 11.0 | 11.0 → latest | No fix stated |
| Node 10.0 | 10.0 → latest | No fix stated |
| Node 9.0 | 9.0 → latest | No fix stated |
| Node 8.0 | 8.0 → latest | No fix stated |
| Node 7.0 | 7.0 → latest | No fix stated |
| Node 6.0 | 6.0 → latest | No fix stated |
| Node 5.0 | 5.0 → latest | No fix stated |
| Node 4.0 | 4.0 → latest | No fix stated |
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