CVE-2026-42505: Invoking Encrypted Client Hello privacy leak in crypto/tls

Published Jul 8, 2026
·
Updated

Handshakes which used Encrypted Client Hello could be de-anonymized by a passive network observer due to a disclosure of pre-shared key identities in the unencrypted client hello.

Affected Software

4 affected components
Google Go>=1.25.12<1.26.5
Golang Go<1.25.12
Golang Go>=1.26.0<1.26.5
Golang Go=1.27-rc1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade Go to a version that resolves this vulnerability.

    Fixed in 1.26.5Patch CVE-2026-39822
  2. Upgrade

    Upgrade Go to a version that resolves this vulnerability.

    Fixed in 1.25.12Patch CVE-2026-42505

Event History

Jul 8, 2026
CVE Published
via MITRE·03:46 PM
Data Sourced
via MITRE·03:46 PM
DescriptionWeakness
Data Sourced
via NVD·05:17 PM
RemedyDescriptionSeverityWeaknessAffected Software
Free Weekly Intel

Don't miss critical vulnerabilities

Join thousands of security professionals who receive our weekly digest of trending CVEs, zero-days, and exploited vulnerabilities.

No spam. Unsubscribe anytime.

Frequently Asked Questions

1

What is the severity of CVE-2026-42505?

CVE-2026-42505 has a medium severity rating of 5.3.

2

What does CVE-2026-42505 expose to attackers?

CVE-2026-42505 can lead to the de-anonymization of handshakes using Encrypted Client Hello, allowing attackers to discern pre-shared key identities.

3

Who is affected by CVE-2026-42505?

CVE-2026-42505 affects software that uses the Google Go crypto/tls library, particularly applications utilizing Encrypted Client Hello.

4

How can I mitigate CVE-2026-42505?

To mitigate CVE-2026-42505, ensure that your application is updated to the latest version of Google Go that includes fixes for this vulnerability.

5

When was CVE-2026-42505 published?

CVE-2026-42505 was published on July 8, 2026.

Company

Resources

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203
CVE-2026-42505 - Invoking Encrypted Client Hello privacy leak in crypto/tls - SecAlerts