Deno: TLS retry copies stale upgrade hook, risking plaintext traffic

{
  "id": "809e708275959bdabe0ccc322f40a5d55f5463af7c3a744db85836afb2bf4fe9",
  "url": "https://osv.dev/vulnerability/CVE-2026-44726",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Deno: TLS retry copies stale upgrade hook, risking plaintext traffic",
    "summary": "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.",
    "evidence": "osv:CVE-2026-44726",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-44726",
      "aliases": [
        "CVE-2026-44726",
        "GHSA-chqv-56wv-7564"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/denoland/deno",
              "type": "GIT",
              "events": [
                {
                  "introduced": "a62c7e036ab6851c0293f407ead635a7331445b7"
                },
                {
                  "fixed": "c394911f8edc7591de8da65c7b6690bcbc78afc1"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "2.0.0"
                      },
                      {
                        "fixed": "2.7.8"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "cpe": "cpe:2.3:a:deno:deno:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "2.0.0"
                      },
                      {
                        "fixed": "2.7.8"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.7.7",
            "v2.7.6",
            "v2.7.5",
            "v2.7.4",
            "v2.7.3",
            "v2.7.2",
            "v2.7.1",
            "v2.7.0",
            "v2.6.10",
            "v2.6.9",
            "v2.6.8",
            "v2.6.7",
            "v2.5.6",
            "v2.6.6",
            "v2.6.5",
            "v2.6.4",
            "v2.6.3",
            "v2.6.2",
            "v2.6.0",
            "v2.3.0",
            "v2.5.5",
            "v2.5.4",
            "v2.5.3",
            "v2.5.2",
            "v2.5.1",
            "v2.5.0",
            "v2.4.5",
            "v2.4.4",
            "v2.4.3",
            "v2.4.2",
            "v2.4.1",
            "v2.4.0",
            "v2.3.7",
            "v2.3.6",
            "v2.3.5",
            "v2.3.4",
            "v2.3.3",
            "v2.3.2",
            "v2.3.1",
            "v2.2.0",
            "v2.1.0",
            "v2.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-44726.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:25.975872537Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44726.json",
        "https://github.com/denoland/deno/security/advisories/GHSA-chqv-56wv-7564",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-44726"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-319"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44726.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-44726",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 492620,
  "published_at": "2026-06-23T17:24:02.702+00:00"
}