PT-2026-50782 · Mcdope · Pam Usb

Published 2026-06-18 · Updated 2026-06-18 · CVE-2026-48981

NVD

CVSS v3.1

6.7

Medium

Base vector

AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:L/A:L

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.

Fix

XXE

Weakness Enumeration

CWE-611

Related Identifiers

CVE-2026-48981

Affected Products

Pam Usb

References · 3

• https://nvd.nist.gov/vuln/detail/CVE-2026-48981 · Security Note
• https://github.com/mcdope/pam_usb/security/advisories/GHSA-96vv-r4wc-28c2 · Note
• https://github.com/mcdope/pam_usb/releases/tag/0.9.2 · Note