CVE-2026-44726
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.
INFO
Published Date :
June 23, 2026, 5:24 p.m.
Last Modified :
June 23, 2026, 5:24 p.m.
Remotely Exploit :
No
Source :
GitHub_M
Affected Products
The following products are affected by CVE-2026-44726
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Update Deno to version 2.7.8 or later.
- Ensure TLS is properly configured for all connections.
- Disable autoSelectFamily if upgrading is not possible.
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