CVE-2026-48792

pam_usb: pusb_has_virtual_input_device() silently discards EACCES, disabling remote desktop detection under non-root execution

State: Published
Severity: 4.4 Medium
Published: May 27, 2026
Updated: May 28, 2026
Reserved: May 22, 2026

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Description

pam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.9.1, src/evdev.c silently ignores EACCES errors when opening /dev/input/event* nodes, causing pusb_has_virtual_input_device() to return 0 (no virtual devices found) even when every open() call failed due to insufficient permissions. The caller in src/local.c cannot distinguish a clean absence of virtual devices from a permission-denied scan, and acts on the false negative by continuing authentication without denying. This vulnerability is fixed in 0.9.1.

Scores

CVSS	Score	Vector	Source
3.1	4.4 Medium	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N	GitHub_M

Weaknesses

CWE-390 Detection of Error Condition Without Action
CWE-693 Protection Mechanism Failure

Affected Products

Product	Versions
pam_usbmcdope	< 0.9.1Affected

References

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