CVE-2025-29991 Security feature bypass in YubiKey
Attackers can bypass PIN/UV authentication checks on YubiKey devices due to incorrect signature length verification in Protocol Two.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2025-29991?
CVE-2025-29991 is a low-severity vulnerability in Yubico YubiKey, published on 3 Apr 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
Yubico YubiKey 5.4.1 through 5.7.3 before 5.7.4 has an incorrect FIDO CTAP PIN/UV Auth Protocol Two implementation. It uses the signature length from CTAP PIN/UV Auth Protocol One, even when CTAP PIN/UV Auth Protocol Two was chosen, resulting in a partial signature verification.
Weakness: CWE-1390
Which versions are affected by CVE-2025-29991?
How do I fix CVE-2025-29991?
No fix has been published for CVE-2025-29991 yet. Limit exposure of the affected software until one is available.
Is CVE-2025-29991 being exploited?
There is no known exploitation of CVE-2025-29991 in the wild and no public exploit code.
Sources
Also known as GHSA-2rq3-x44v-xx2w.