CVE-2026-48981
MEDIUM
MEDIUM
Priority: 0.01
BB Relevance:
23/100
Published: 2026-06-18
Modified: 2026-10-26
First seen: 2026-10-29
Status: active
Attack Surface
No Interaction
Conf. Impact
Scope Change
CVSS Vector Breakdown
AV:
Local
AC:
High
PR:
High
UI:
None
S:
Changed
C:
High
I:
Low
A:
Low
Description
pam_usb provides hardware authentication for Linux using ordinary removable media. In versions prior to 0.9.2, pam_usb calls xmlReadFile() with flags=0 when loading the configuration file, allowing libxml2 to process external entity references (XXE), potentially making outbound network connections or local file reads at XML parse time from the context of the authenticating process. The vulnerability requires the configuration file to contain crafted XML entity references. Since pam_usb.conf is root-owned, direct exploitation requires prior write access to the config, but the defence-in-depth impact is significant given that pam_usb.so runs in setuid contexts (sudo, su). This issue has been fixed in version 0.9.2.