CVE-2026-44726: Deno is a JavaScript, TypeScript, and WebAssembly runtime. From 2.0.0 until 2.7.8, a flaw in Deno's Node.js tls compatibility layer could cause a TLS client to…

PriorityP351critical9.1CVSS 3.1

AVNACLPRNUINSUCHIHAN

EPSS

0.23%

14.6th percentile

Deno is a JavaScript, TypeScript, and WebAssembly runtime. From 2.0.0 until 2.7.8, a flaw in Deno's Node.js tls compatibility layer could cause a TLS client to transmit application data in plaintext after a connection retry. When `autoSelectFamily was enabled and the first address-family attempt failed, the socket reinitialization path reused a stale TLS upgrade hook that was bound to the original, failed handle. As a result, the replacement TCP connection was never upgraded to TLS, and any data the application wrote before the secureConnect event travelled over the network unencrypted. A network attacker positioned to cause the initial connection attempt to fail (for example, by dropping IPv6 traffic on a dual-stack host) could deterministically trigger the fallback path and observe or tamper with traffic that the application believed was TLS-protected. This vulnerability is fixed in 2.7.8.

Affected

3 ranges

Vendor	Product	Version range	Fixed in
deno	deno	>= 2.0.0 < 2.7.8	2.7.8
deno	deno	>= 2.0.0 < 2.7.8	2.7.8
denoland	deno	—	—

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