Vulnerability Report: GO-2026-5019

CVE-2026-39831
Affects: golang.org/x/crypto
Published: May 22, 2026

The Verify() method for FIDO/U2F security key types (sk-ecdsa-sha2-nistp256@openssh.com, sk-ssh-ed25519@openssh.com) 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.

Affected Packages

Path

Go Versions

Symbols
golang.org/x/crypto/ssh

before v0.52.0
7 affected symbols

Aliases

CVE-2026-39831

References

https://go.dev/issue/79566
https://groups.google.com/g/golang-announce/c/a082jnz-LvI
https://go.dev/cl/781662
https://vuln.go.dev/ID/GO-2026-5019.json

Credits

NCC Group Cryptography Services, sponsored by Teleport

Feedback

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