CVE-2026-48980: pam_usb: getenv() used in PAM context allows environment variable injection into local-check logic

Vulnerability summary

CVE-2026-48980 is a medium (CVSS 6.3) vulnerability in mcdope pam_usb. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 6.7% of scored vulnerabilities.

Timeline

1. 18-06-2026
   PublishedVulnerability first disclosed.
2. 18-06-2026
   Last modifiedVulnerability information updated.

Description

pam_usb provides hardware authentication for Linux using removable media. In versions prior to 0.9.2, getenv() environment variables XRDP_SESSION, DISPLAY and TMUX allow environment variable injection into local-check logic. These environment variables influence whether a current session is local or remote, and a PAM module that runs in the context of setuid binaries (sudo, su), getenv() returns attacker-controlled values whenever the process environment has been manipulated by a local user. This issue has been fixed in version 0.9.2.

• CWE-454External Initialization of Trusted Variables or Data StoresThe product initializes critical internal variables or data stores using inputs that can be modified by untrusted actors.
• CWE-807Reliance on Untrusted Inputs in a Security DecisionThe product uses a protection mechanism that relies on the existence or values of an input, but the input can be modified by an untrusted actor in a way that bypasses the protection mechanism.