CVE-2026-39831 — CRITICAL (9.1)

Q: How severe is CVE-2026-39831?

CVE-2026-39831 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.

Q: Is there a patch for CVE-2026-39831?

Check the references section above for vendor advisories and patch information. Affected products include: Golang Crypto.

Vulnerability Description

The 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.

CVSS Score

9.1

CRITICAL

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

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

NONE

Affected Products

Vendor	Product	Versions
Golang	Crypto	< 0.52.0

Related Weaknesses (CWE)

CWE-862

References

https://go.dev/cl/781662Issue Tracking
https://go.dev/issue/79566Issue Tracking
https://groups.google.com/g/golang-announce/c/a082jnz-LvIMailing List
https://pkg.go.dev/vuln/GO-2026-5019Vendor Advisory

FAQ

What is CVE-2026-39831?

CVE-2026-39831 is a vulnerability with a CVSS score of 9.1 (CRITICAL). The Verify() method for FIDO/U2F security key types ([email protected], [email protected]) did not check the User Presence flag. Signatures generated without physical touch w...

How severe is CVE-2026-39831?

CVE-2026-39831 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.

Is there a patch for CVE-2026-39831?

Check the references section above for vendor advisories and patch information. Affected products include: Golang Crypto.