Invoking bypass of FIDO/U2F security keys physical interaction in golang.org/x/crypto/ssh
Summary
| CVE | CVE-2026-39831 |
|---|---|
| State | PUBLISHED |
| Assigner | Go |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-05-22 04:16:22 UTC |
| Updated | 2026-05-22 04:16:22 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 9.1 CRITICAL from ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS: 0.000290000 probability, percentile 0.089650000 (date 2026-05-28)
Problem Types: CWE-290: Authentication Bypass by Spoofing
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
NoneCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Golang.orgxcrypto | Golang.org/x/crypto/ssh | affected 0.52.0 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| groups.google.com/g/golang-announce/c/a082jnz-LvI | [email protected] | groups.google.com | |
| pkg.go.dev/vuln/GO-2026-5019 | [email protected] | pkg.go.dev | |
| go.dev/cl/781662 | [email protected] | go.dev | |
| go.dev/issue/79566 | [email protected] | go.dev | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: NCC Group Cryptography Services, sponsored by Teleport (en)
There are currently no legacy QID mappings associated with this CVE.