TLS Vulnerability in Deno Affects Data Security
CVE-2026-44726

7.4HIGH

Key Information:

Vendor

Denoland

Status
Deno
Vendor
CVE Published:
23 June 2026

What is CVE-2026-44726?

A security flaw in Deno's TLS compatibility layer could allow application data to be transmitted in plaintext under certain conditions. Versions 2.0.0 to 2.7.8 are affected. When 'autoSelectFamily' was enabled, if the initial connection attempt using IPv6 failed, the system would attempt to fallback to a TCP connection without upgrading to TLS. Consequently, this flawed process could expose sensitive data during transmission, as an attacker could leverage the situation to intercept or modify the supposedly secure traffic. The vulnerability is addressed in version 2.7.8 of Deno.

Affected Version(s)

deno >= 2.0.0, < 2.7.8

References

https://github.com/denoland/deno/security/advisories/GHSA...
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CVSS V3.1

Score:
7.4
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.