CVE-2026-39831

CriticalCVSS 9.1/10Last modified Jul 23, 2026

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.

Metrics

CVSS 3.1 9.1/10CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Weakness enumeration

CWE-862

Affected software

No affected versions have been published.

Timeline

Published: May 22, 2026
Last modified: Jul 23, 2026
NVD status: Analyzed

Related CVEs from 2026

CVE-2026-398329.1When adding a key to a remote agent constraint extensions such as restrict-destination-v00@openssh.com were not serialized in the request. D CVE-2026-398339.1The in-memory keyring returned by NewKeyring() silently accepted keys with the ConfirmBeforeUse constraint but never enforced it. The key wo CVE-2026-398349.1When writing data larger than 4GB in a single Write call on an SSH channel, an integer overflow in the internal payload size calculation cau CVE-2026-398355.3SSH servers which use CertChecker as a public key callback without setting IsUserAuthority or IsHostAuthority could be caused to panic by a CVE-2026-398367.5The Dial and LookupPort functions panic on Windows when provided with an input containing a NUL (0).CVE-2026-398375.4Improper neutralization of Script-Related HTML tags in a web page (basic XSS) vulnerability in WikiWorks Mediawiki - Cargo Extension allows CVE-2026-398386.9Improper neutralization of input during web page generation ('cross-site scripting') vulnerability in Wikimedia Foundation MediaWiki - Proof CVE-2026-398396.1Improper neutralization of Script-Related HTML tags in a web page (basic XSS) vulnerability in Wikimedia Foundation Mediawiki - Cargo Extens CVE-2026-39843.5A weakness has been identified in Campcodes Division Regional Athletic Meet Game Result Matrix System 2.1. This vulnerability affects unknow CVE-2026-398406.1Improper neutralization of input during web page generation ('cross-site scripting') vulnerability in Wikimedia Foundation Mediawiki - Cargo CVE-2026-398416.1Improper neutralization of Script-Related HTML tags in a web page (basic XSS) vulnerability in Wikimedia Foundation Mediawiki - Cargo Extens CVE-2026-398429.9OpenRemote is an open-source IoT platform. Versions 1.21.0 and below contain two interrelated expression injection vulnerabilities in the ru