An issue was discovered in Nitrokey FIDO U2F firmware through 1.1. Communication between the microcontroller and the secure element transmits credentials in plain. This allows an adversary to eavesdrop the communication and derive the secrets stored in the microcontroller. As a result, the attacker is able to arbitrarily manipulate the firmware of the microcontroller.
An official patch is available. Apply the patch as soon as possible.
CVSS v4.0 Metrics
Exploitability
Attack VectorNetwork
ComplexityLow
RequirementsPresent
PrivilegesNone
User InteractionNone
Threat
Exploit MaturityPoC
Vulnerable System
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
Subsequent System
ConfidentialityNone
IntegrityNone
AvailabilityNone
Supplemental
SafetyNegligible
AutomatableYes
RecoveryAutomatic
Value DensityConcentrated
UrgencyMedium
Patch StatusOfficial Patch
Change Log
| Date | Source | Changes | Score |
|---|
| 2026-07-21 | PoC | E: U→P | 7.2 → 8.2 |
| 2026-07-21 | nvd | AV: P→N, AC: H→L, PR: H→N, UI: A→N, VC: N→H, VI: N→H, VA: N→H | 0.0 → 7.2 |
| 2026-07-21 | nvd | patch: Unavailable→Official Patch | 0.0 → 0.0 |
| 2026-07-21 | cve.org | initial, patch: Unavailable | 0.0 |
Affected Software
| Vendor | Product | Version |
|---|
| nitrokey | fido_u2f_firmware | ≤ 1.1 |
Published: 2021-05-21
