CVE-2021-31924

published 2021-05-26

CVE-2021-31924: Yubico pam-u2f before 1.1.1 has a logic issue that, depending on the pam-u2f configuration and the application used, could lead to a local PIN bypass. This…

Priority P4 31 medium 6.8 CVSS 3.1

AV P AC L PR N UI N S U C H I H A H

Yubico pam-u2f before 1.1.1 has a logic issue that, depending on the pam-u2f configuration and the application used, could lead to a local PIN bypass. This issue does not allow user presence (touch) or cryptographic signature verification to be bypassed, so an attacker would still need to physically possess and interact with the YubiKey or another enrolled authenticator. If pam-u2f is configured to require PIN authentication, and the application using pam-u2f allows the user to submit NULL as the PIN, pam-u2f will attempt to perform a FIDO2 authentication without PIN. If this authentication is successful, the PIN requirement is bypassed.

Affected

8 ranges

Vendor	Product	Version range	Fixed in
debian	pam-u2f	< pam-u2f 1.1.0-1.1 (bookworm)	pam-u2f 1.1.0-1.1 (bookworm)
fedoraproject	fedora	—	—
fedoraproject	fedora	—	—
yubico	pam-u2f	< 1.1.1	1.1.1
yubico	pam-u2f	>= 0 < 1.1.0-1.1	1.1.0-1.1
yubico	pam-u2f	>= 0 < 1.1.0-1.1	1.1.0-1.1
yubico	pam-u2f	>= 0 < 1.1.0-1.1	1.1.0-1.1
yubico	pam-u2f	>= 0 < 1.1.0-1.1	1.1.0-1.1

CVSS provenance

nvd v3.1 6.8 MEDIUM CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd v2.0 4.6 MEDIUM AV:L/AC:L/Au:N/C:P/I:P/A:P

osv 6.8 MEDIUM

vendor_debian 6.8 MEDIUM

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CWE-287