Description
An issue was discovered in the selinux-policy (aka Reference Policy) package 3.14 through 2020-08-24 because the .config/Yubico directory is mishandled. Consequently, when SELinux is in enforced mode, pam-u2f is not allowed to read the user's U2F configuration file. If configured with the nouserok option (the default when configured by the authselect tool), and that file cannot be read, the second factor is disabled. An attacker with only the knowledge of the password can then log in, bypassing 2FA.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | refpolicy | No fix yet | — |
| Ubuntu 26.04 LTS | refpolicy | No fix yet | — |
| Ubuntu 25.10 | refpolicy | No fix yet | — |
| Ubuntu 24.04 LTS | refpolicy | No fix yet | — |
| Ubuntu 22.04 LTS | refpolicy | No fix yet | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | refpolicy | No fix yet | — |
| Ubuntu 18.04 LTS | refpolicy | No fix yet | — |
| Ubuntu 16.04 LTS | refpolicy | No fix yet | — |
| Ubuntu 14.04 LTS | refpolicy | No fix yet | — |