Hardware Authentication Vulnerability in pam_usb for Linux
CVE-2026-64666

7.1HIGH

Key Information:

Vendor

Mcdope

Status
Pam Usb
Vendor
CVE Published:
11 November 2026

What is CVE-2026-64666?

A security flaw in pam_usb affects Linux systems by allowing unauthorized manipulation of the XRDP_SESSION environment variable. Prior to version 0.9.3, pam_usb's handling of this variable can be exploited in a setuid PAM host, bypassing strict XRDP-deny rules. Although other mechanisms may detect this session, the environment-based detection is easily circumvented, posing a risk to system security. Users are advised to update to version 0.9.3 to mitigate this issue.

Affected Version(s)

pam_usb < 0.9.3

References

https://github.com/mcdope/pam_usb/security/advisories/GHS...
x_refsource_CONFIRM
https://github.com/mcdope/pam_usb/issues/410
x_refsource_MISC
https://github.com/mcdope/pam_usb/pull/417
x_refsource_MISC

CVSS V3.1

Score:
7.1
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.