pam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.9.1, when a PAM service is configured with deny_remote=false in pam_usb (commonly done for display managers such as gdm-password or lightdm to bypass process/TTY heuristics for local sessions), the PAM_RHOST check in pusb_do_auth() is also skipped. PAM_RHOST is set by remote daemons (sshd, XDMCP servers) to identify the remote client address. Because the check is gated inside if (opts.deny_remote), a genuine remote XDMCP connection reaches the USB device authentication step instead of being rejected. This vulnerability is fixed in 0.9.1.
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History
Wed, 27 May 2026 20:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | pam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.9.1, when a PAM service is configured with deny_remote=false in pam_usb (commonly done for display managers such as gdm-password or lightdm to bypass process/TTY heuristics for local sessions), the PAM_RHOST check in pusb_do_auth() is also skipped. PAM_RHOST is set by remote daemons (sshd, XDMCP servers) to identify the remote client address. Because the check is gated inside if (opts.deny_remote), a genuine remote XDMCP connection reaches the USB device authentication step instead of being rejected. This vulnerability is fixed in 0.9.1. | |
| Title | pam_usb: PAM_RHOST check skipped when deny_remote=false allows XDMCP authentication bypass | |
| Weaknesses | CWE-863 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-05-27T19:59:53.496Z
Reserved: 2026-05-20T18:25:25.707Z
Link: CVE-2026-48064
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Status : Received
Published: 2026-05-27T20:16:40.230
Modified: 2026-05-27T20:16:40.230
Link: CVE-2026-48064
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OpenCVE Enrichment
Updated: 2026-05-27T22:00:17Z
Weaknesses