CVE-2026-44726

[CVE catalog]

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.

Severity

High · CVSS 7.4CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Published

Jun 23, 2026, 6:17:48 PM UTC

Source

[NVD] · [CVE record]

EPSS

0.23% · Oct 27, 2026

{
  "package_releases": [],
  "fixed_versions": [],
  "distribution_packages": [
    {
      "name": "deno",
      "ecosystem": "cpe",
      "fixed_version": "2.7.8"
    },
    {
      "name": "deno",
      "ranges": [
        {
          "fixed": "2.7.8",
          "introduced": "2.0.0",
          "last_affected": "",
          "start_excluding": ""
        }
      ],
      "ecosystem": "cpe",
      "fixed_version": "2.7.8",
      "provider_record_id": "NVD-CVE-2026-44726"
    }
  ]
}