Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Deno | Deno | >= 2.0.0, < 2.7.8 |
Related Weaknesses (CWE)
References
- https://github.com/denoland/deno/security/advisories/GHSA-chqv-56wv-7564ExploitVendor Advisory
FAQ
What is CVE-2026-44726?
CVE-2026-44726 is a vulnerability with a CVSS score of 7.4 (HIGH). 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 a...
How severe is CVE-2026-44726?
CVE-2026-44726 has been rated HIGH with a CVSS base score of 7.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-44726?
Check the references section above for vendor advisories and patch information. Affected products include: Deno Deno.