Critical 9.1Published May 21, 2026

CVE-2026-39831Invoking bypass of FIDO/U2F security keys physical interaction in golang.org/x/crypto/ssh

Updated under an hour ago (Oct 27, 2026, 5:10 PM ET)

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It affects golang.org/x/crypto/ssh and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for golang.org/x/crypto/ssh

Exploited in the last 30 days

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.

CVSS: 9.1 CRITICAL (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness (CWE): CWE-290
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Go
NVD analysis: Analyzed
Record last updated: May 22, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

golang.org/x/crypto golang.org/x/crypto/ssh golang.org_x_crypto:ssh (from the name)	before 0.52.0	CNA record
golang crypto golang:crypto	before 0.52.0	NVD

References

References

https://go.dev/issue/79566	issue-tracking
https://groups.google.com/g/golang-announce/c/a082jnz-LvI	mailing-list
https://go.dev/cl/781662	issue-tracking
https://pkg.go.dev/vuln/GO-2026-5019	vendor-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.