CVE-2026-48980

Local authentication bypass via untrusted environment variables

Published Jun 18, 2026 · Updated Jun 18, 2026

Authentication bypass in mcdope pam_usb before 0.9.2 allows local users to bypass USB checks in privileged PAM consumers. The local-session checks in src/local.c and src/tmux.c use getenv() for XRDP_SESSION, DISPLAY, and TMUX, so setuid callers consume attacker-controlled process-environment values. A local low-privileged account able to influence the environment of sudo, su, or another PAM consumer can make a remote session appear local and defeat the configured removable-media authentication gate.

CVSS severity6.3
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in mcdope pam_usb before 0.9.2 allows local users to bypass USB checks in privileged PAM consumers. The local-session checks in src/local.c and src/tmux.c use getenv() for XRDP_SESSION, DISPLAY, and TMUX, so setuid callers consume attacker-controlled process-environment values. A local low-privileged account able to influence the environment of sudo, su, or another PAM consumer can make a remote session appear local and defeat the configured removable-media authentication gate.

The record

CVE
CVE-2026-48980
Published
Jun 18, 2026
Updated
Jun 18, 2026
Vendor
mcdope
Product
pam_usb
Classifications
CWE-807, CWE-454, T1548.003
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.9.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

mcdope · pam_usbversion=< 0.9.2

Published CVSS scores

6.3GitHubCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-807Reliance on Untrusted Inputs in a Security Decision
CWE-454External Initialization of Trusted Variables or Data Stores
T1548.003Sudo and Sudo Caching

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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