Description
In check_user_token in util.c in the Yubico PAM module (aka pam_yubico) 2.18 through 2.25, successful logins can leak file descriptors to the auth mapping file, which can lead to information disclosure (serial number of a device) and/or DoS (reaching the maximum number of file descriptors).
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.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | yubico-pam | 2.26-1 | — |
| Debian 13 | yubico-pam | 2.26-1 | — |
| Debian 12 | yubico-pam | 2.26-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | yubico-pam | No fix yet | — |
| Ubuntu 16.04 LTS | yubico-pam | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | pam_yubico | 2.27-1.5 | openSUSE-SU-2024:11146-1 |
Advisories 1
- openSUSE-SU-2024:11146-1 pam_yubico-2.27-1.5 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026