Gentoo Websites Logo
Go to: Gentoo Home Documentation Forums Lists Bugs Planet Store Wiki Get Gentoo!
Bug 792270 (CVE-2021-31924, YSA-2021-03) - <sys-auth/pam_u2f-1.1.1: Local PIN bypass (CVE-2021-31924)
Summary: <sys-auth/pam_u2f-1.1.1: Local PIN bypass (CVE-2021-31924)
Alias: CVE-2021-31924, YSA-2021-03
Product: Gentoo Security
Classification: Unclassified
Component: Vulnerabilities (show other bugs)
Hardware: All Linux
: Normal normal (vote)
Assignee: Gentoo Security
Whiteboard: B3 [glsa?]
Depends on:
Reported: 2021-05-26 16:46 UTC by Sam James
Modified: 2021-07-26 03:26 UTC (History)
1 user (show)

See Also:
Package list:
Runtime testing required: ---
nattka: sanity-check+


Note You need to log in before you can comment on or make changes to this bug.
Description Sam James archtester gentoo-dev Security 2021-05-26 16:46:19 UTC
"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."
Comment 1 Sam James archtester gentoo-dev Security 2021-05-26 16:46:55 UTC
Please bump to 1.1.1.
Comment 2 Larry the Git Cow gentoo-dev 2021-06-01 18:27:00 UTC
The bug has been referenced in the following commit(s):

commit 61975a03862b41f57868867e8aeec85643aa4c94
Author:     David Seifert <>
AuthorDate: 2021-06-01 18:26:45 +0000
Commit:     David Seifert <>
CommitDate: 2021-06-01 18:26:45 +0000

    sys-auth/pam_u2f: add 1.1.1
    Signed-off-by: David Seifert <>

 sys-auth/pam_u2f/Manifest             |  1 +
 sys-auth/pam_u2f/pam_u2f-1.1.1.ebuild | 39 +++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)
Comment 3 Sam James archtester gentoo-dev Security 2021-06-21 07:08:22 UTC
Comment 4 Sam James archtester gentoo-dev Security 2021-06-25 01:19:57 UTC
I'll CC arches if no objections?
Comment 5 Agostino Sarubbo gentoo-dev 2021-06-27 05:57:44 UTC
amd64 stable
Comment 6 Agostino Sarubbo gentoo-dev 2021-06-27 05:58:28 UTC
x86 stable.

Maintainer(s), please cleanup.
Security, please vote.
Comment 7 Larry the Git Cow gentoo-dev 2021-07-26 03:24:57 UTC
The bug has been referenced in the following commit(s):

commit 1244305b9284cf3cf0527fdac223920a5de8fde9
Author:     John Helmert III <>
AuthorDate: 2021-07-25 20:33:06 +0000
Commit:     John Helmert III <>
CommitDate: 2021-07-26 03:12:43 +0000

    sys-auth/pam_u2f: drop 1.1.0
    Signed-off-by: John Helmert III <>

 sys-auth/pam_u2f/Manifest                          |  1 -
 .../pam_u2f/files/pam_u2f-1.0.2-fix-Makefile.patch | 13 -------
 .../files/pam_u2f-1.1.0-include-limits_h.patch     | 41 ----------------------
 sys-auth/pam_u2f/pam_u2f-1.1.0.ebuild              | 37 -------------------
 4 files changed, 92 deletions(-)