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

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.

Scores

EPSS (exploitation in 30 days)

0.18% · top 93% of all CVEs (5 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: total

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.3.

Weakness

• CWE-454: External Initialization of Trusted Variables or Data Stores (opens in a new tab)All about CWE-454 and its CVEs
• CWE-807: Reliance on Untrusted Inputs in a Security Decision (opens in a new tab)All about CWE-807 and its CVEs

Affected products

• mcdope · pam_usb

  • affected < 0.9.2

References (2)

• https://github.com/mcdope/pam_usb/security/advisories/GHSA-qr83-mf3h-fvqr (opens in a new tab)x_refsource_CONFIRM
• https://github.com/mcdope/pam_usb/releases/tag/0.9.2 (opens in a new tab)x_refsource_MISC

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-48980](https://trackcve.app/badge/CVE-2026-48980.svg)](https://trackcve.app/cve/CVE-2026-48980)

Record last updated 18 Jun 2026, 20:25 UTC.