Invoking Encrypted Client Hello privacy leak in crypto/tls

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-42505
StatePUBLISHED
AssignerGo
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-08 17:17:21 UTC
Updated2026-07-13 17:05:36 UTC
DescriptionHandshakes 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.

Risk And Classification

Primary CVSS: v3.1 5.3 MEDIUM from ADP

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

EPSS: 0.004190000 probability, percentile 0.338530000 (date 2026-07-13)

Problem Types: CWE-201 | CWE-201: Insertion of Sensitive Information Into Sent Data | CWE-201 CWE-201 Insertion of Sensitive Information Into Sent Data

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Golang Go All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Go Standard Library Crypto/tls affected 1.25.12 semver Not specified
CNA Go Standard Library Crypto/tls affected 1.26.0-0 1.26.5 semver Not specified
CNA Go Standard Library Crypto/tls affected 1.27.0-0 1.27.0-rc.2 semver Not specified

References

ReferenceSourceLinkTags
go.dev/issue/79282 [email protected] go.dev Issue Tracking, Patch
go.dev/cl/775960 [email protected] go.dev Patch
pkg.go.dev/vuln/GO-2026-5856 [email protected] pkg.go.dev Vendor Advisory
groups.google.com/g/golang-announce/c/OrmQE_Yp5Sc [email protected] groups.google.com Mailing List, Release Notes, Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Coia Prant (github.com/rbqvq) (en)

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