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.

No CVSS v4.0

Attack Vector Local

Attack Complexity High

Privileges Required High

Scope Changed

Confidentiality Impact High

Integrity Impact Low

Availability Impact Low

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
mcdope pam_usb affected
Version Status Constraints
< 0.9.2 affected —

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Vendors Products
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Pam Usb Subscribe

Project Subscriptions

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Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/mcdope/pam_usb/releases/tag/0.9.2 cve-icon
https://github.com/mcdope/pam_usb/security/advisories/GHSA-96vv-r4wc-28c2 cve-icon
History

Thu, 18 Jun 2026 21:30:00 +0000

Type Values Removed Values Added
First Time appeared Mcdope
Mcdope pam Usb
Vendors & Products Mcdope
Mcdope pam Usb

Thu, 18 Jun 2026 19:45:00 +0000

Type Values Removed Values Added
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.
Title pam_usb: xmlReadFile flags=0 permits XXE network entity fetching in conf.c
Weaknesses CWE-611
References
Metrics cvssV3_1

{'score': 6.7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:L/A:L'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-18T18:55:58.485Z

Reserved: 2026-05-26T23:26:07.974Z

Link: CVE-2026-48981

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-18T21:30:16Z

Weaknesses