DEBIAN-CVE-2026-21637
Record from OSV · Published January 20, 2026
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.
Fixed versions
Upgrade to a fixed version or later. Language registries are listed first, then Linux distributions, then vendor products.
| Package | Ecosystem | Fixed in |
|---|---|---|
| nodejs | Debian:13 | 20.19.2+dfsg-1+deb13u2 |
| nodejs | Debian:12 | 18.20.4+dfsg-1~deb12u2 |
| nodejs | Debian:14 | 22.22.2+dfsg+~cs22.19.15-1 |
Risk scores
Affected products
| Vendor | Product | Versions |
|---|---|---|
| Debian:13 | nodejs | 0, 20.19.2+dfsg-1, 20.19.2+dfsg-1+deb13u1 |
| Debian:12 | nodejs | 0, 18.13.0+dfsg1-1, 18.13.0+dfsg1-1.1 |
| Debian:14 | nodejs | 0, 22.22.1+dfsg+~cs22.19.15-1, 20.19.2+dfsg-1 |
Timeline
- Jan 20, 2026 CVE Published
- Oct 1, 2026 CVE Updated
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