Invoking bypass of FIDO/U2F security keys physical interaction in golang.org/x/crypto/ssh

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2026-39831
StatePUBLISHED
AssignerGo
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-22 04:16:22 UTC
Updated2026-06-02 16:33:18 UTC
DescriptionThe Verify() method for FIDO/U2F security key types ([email protected], [email protected]) did not check the User Presence flag. Signatures generated without physical touch were accepted, allowing unattended use of a hardware security key. To restore the previous behavior, return a "no-touch-required" extension in Permissions.Extensions from PublicKeyCallback.

Risk And Classification

Primary CVSS: v3.1 9.1 CRITICAL from ADP

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

EPSS: 0.000330000 probability, percentile 0.099370000 (date 2026-06-08)

Problem Types: CWE-862 | CWE-290: Authentication Bypass by Spoofing

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS v3.1 Breakdown

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

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Golang Crypto All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Golang.orgxcrypto Golang.org/x/crypto/ssh affected 0.52.0 semver Not specified

References

ReferenceSourceLinkTags
groups.google.com/g/golang-announce/c/a082jnz-LvI [email protected] groups.google.com Mailing List
pkg.go.dev/vuln/GO-2026-5019 [email protected] pkg.go.dev Vendor Advisory
go.dev/cl/781662 [email protected] go.dev Issue Tracking
go.dev/issue/79566 [email protected] go.dev Issue Tracking
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: NCC Group Cryptography Services, sponsored by Teleport (en)

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