CVE-2026-42505 | Handshakes which used Encrypted Client Hello could be de-ano… | CVSS 5.3 MEDIUM

Description

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.

Metadata

CVE ID: CVE-2026-42505
State: PUBLISHED
Assigner: Go
Reserved: 2026-04-28 00:21 UTC
Published: 2026-07-08 15:46 UTC
Last updated: 2026-07-08 19:38 UTC
Primary CWE: CWE-201
CWE-201 Insertion of Sensitive Information Into Sent Data
Vendor / Product: Go standard library / crypto/tls
Sources: cve.org · NVD

Severity & Metrics

5.3 MEDIUM CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

SSVC — CISA Coordinator

Exploitation: none
Automatable: yes
Tech. Impact: partial

Affected products (1)

Vendor	Product	Platform	Versions
Go standard library	crypto/tls	—	0 < 1.25.12, 1.26.0-0 < 1.26.5, 1.27.0-0 < 1.27.0-rc.2

Weakness (CWE)

CWE	Source	Description
—	cna	CWE-201: Insertion of Sensitive Information Into Sent Data
CWE-201	adp	CWE-201 Insertion of Sensitive Information Into Sent Data

CVSS scores (1)

Score	Severity	Version	Source	Vector
5.3	MEDIUM	3.1	adp	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References (4)