CVE-2026-42505

A flaw was found in the crypto/tls package in Go. Handshakes utilizing Encrypted Client Hello (ECH) could lead to de-anonymization by a passive network observer. This is due to the disclosure of pre-shared key identities within the unencrypted client hello, allowing an attacker to potentially link connections.

This Moderate-impact information disclosure flaw in the Go crypto/tls package allows a passive network observer to de-anonymize connections utilizing Encrypted Client Hello (ECH). The vulnerability stems from the unintentional exposure of pre-shared key identities within the unencrypted client hello, potentially enabling an attacker to link previously anonymous connections. This primarily affects the privacy of communications rather than integrity or availability.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.