CVE-2025-29991

Reduced FIDO command integrity via truncated signature verification

Published Apr 3, 2025 · Updated Apr 3, 2025

Weak authentication in Yubico YubiKey 5.4.1 through 5.7.3 allows local users to submit partially verified FIDO commands. The PIN/UV Auth Protocol Two verifier checks only the first 16 bytes of the required 32-byte HMAC-SHA-256 signature, reusing Protocol One length. Exploitation requires local access, low privileges, and user interaction; retained protocol protections make exploitation difficult and bound the consequence to reduced command integrity.

CVSS severity2.2
Low
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Weak authentication in Yubico YubiKey 5.4.1 through 5.7.3 allows local users to submit partially verified FIDO commands. The PIN/UV Auth Protocol Two verifier checks only the first 16 bytes of the required 32-byte HMAC-SHA-256 signature, reusing Protocol One length. Exploitation requires local access, low privileges, and user interaction; retained protocol protections make exploitation difficult and bound the consequence to reduced command integrity.

The record

CVE
CVE-2025-29991
Published
Apr 3, 2025
Updated
Apr 3, 2025
Vendor
Yubico
Product
YubiKey
Classifications
CWE-1390
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 3, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.4.1 <5.7.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Yubico · YubiKeyversion=5.4.1 <5.7.4

Published CVSS scores

2.2MITRECVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1390Weak Authentication

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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