{"id":"CVE-2026-44726","state":"PUBLISHED","title":"Deno: TLS retry copies stale upgrade hook, risking plaintext traffic","description":"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.","publishedAt":"2026-06-23T17:24:02.702Z","updatedAt":"2026-06-25T13:48:50.170Z","severity":{"score":7.4,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["denoland deno"],"affected":[{"vendor":"denoland","product":"deno","versions":[{"version":">= 2.0.0, < 2.7.8","status":"affected"}]}],"references":["https://github.com/denoland/deno/security/advisories/GHSA-chqv-56wv-7564"],"weaknesses":["CWE-319"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/44xxx/CVE-2026-44726.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-44726","state":"PUBLISHED","datePublished":"2026-06-23T17:24:02.702Z","dateUpdated":"2026-06-25T13:48:50.170Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-05-07T18:04:17.308Z"},"containers":{"cna":{"title":"Deno: TLS retry copies stale upgrade hook, risking plaintext traffic","descriptions":[{"lang":"en","value":"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":[{"vendor":"denoland","product":"deno","versions":[{"version":">= 2.0.0, < 2.7.8","status":"affected"}]}],"references":[{"url":"https://github.com/denoland/deno/security/advisories/GHSA-chqv-56wv-7564","name":"https://github.com/denoland/deno/security/advisories/GHSA-chqv-56wv-7564","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.4,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-319","lang":"en","description":"CWE-319: Cleartext Transmission of Sensitive Information","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-06-23T17:24:02.702Z"},"source":{"advisory":"GHSA-chqv-56wv-7564","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-25T03:55:51.795074Z","id":"CVE-2026-44726","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-25T13:48:50.170Z"}}]}}}