pam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.9.0, pam_usb builds XPath expressions from user-supplied identifiers (PAM username, service name) and device-supplied identifiers (USB device serial, model, vendor) to query /etc/pamusb.conf. These identifiers were not validated for XPath metacharacters, allowing injection of arbitrary XPath predicates. This vulnerability is fixed in 0.9.0.
Exploitability
AV:NAC:HPR:NUI:NScope
S:UImpact
C:LI:HA:N6.5/CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:NOther