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CVE-2026-39831

NVD

https://nvd.nist.gov/vuln/detail/CVE-2026-39831

Severity

9.1

Critical

CVSS V3

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Summary

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

Description

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.

References

Affected packages

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