Crypto Tls EUVD-2026-20014

This vulnerability affects the Go standard library's crypto/tls implementation, specifically the handling of TLS 1.3 post-handshake key update messages as defined in RFC 8446. In TLS 1.3, KeyUpdate messages allow either peer to request cryptographic key material refresh without full renegotiation. The Go crypto/tls package fails to properly handle scenarios where an attacker sends multiple KeyUpdate messages bundled within a single TLS record (rather than separate records). This triggers a deadlock condition in the connection state machine, causing the TLS session to hang indefinitely and consume resources (CPU cycles, memory buffers, goroutines) without releasing them. The flaw is specific to TLS 1.3's post-handshake messaging mechanism and does not affect TLS 1.2 or earlier protocols, which lack this key update feature. The affected CPE (cpe:2.3:a:go_standard_library:crypto/tls) indicates any Go application using the standard library's TLS implementation for server or client operations with TLS 1.3 enabled is potentially vulnerable.