CVE•Published 2026-05-22•Modified 2026-06-02•1 article on news•6 live references•NVD data
CVE-2026-39831Golang · Crypto
Vulnerability data via NVD (ingested)
CVSS v3.1
9.1
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS percentile
—
Weaknesses (CWE)
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.
Timeline
Published 2026-05-22
Modified 2026-06-02
External references
Search for exposed instances
Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).
Shodan · vuln tag0 hosts
vuln:CVE-2026-39831Hosts Shodan has explicitly fingerprinted as vulnerable.
Shodan · product
product:"Golang Crypto"All exposed Golang Crypto instances — cross-reference with the CVE's affected-version range.
Shodan · banner/body mention
http.html:"Crypto"HTTP body or banner mentions "Crypto" — catches deploys Shodan didn't identify as a product.
More intel sources (5)
Shodan report
vuln:CVE-2026-39831Country / ASN / product breakdown for the vuln query.
Censys
vulnerabilities.cve_id: CVE-2026-39831Censys host search filtered to this CVE id.
grep.app
CVE-2026-39831Public source-code mentions — fast PoC discovery.
GitHub code
CVE-2026-39831GitHub code search for direct mentions.
Google dork
"CVE-2026-39831" exploit -site:nvd.nist.govWrite-ups and news, NVD excluded.
Known PoCs on GitHub
No public proof-of-concept repositories found for CVE-2026-39831 on GitHub.