Vulnerability · Published May 27, 2026 · Assigned by GitHub_M

CVE-2026-48792pam_usb: pusb_has_virtual_input_device() silently discards EACCES, disabling remote desktop detection under non-root execution

Medium 4.4

In plain English

A medium-severity security flaw in pam_usb from mcdope. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 3% of all known vulnerabilities).

Severity (CVSS 3.1)4.4Medium

Exploit odds (30 days)0.1%top 97.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
mcdope	pam_usb	< 0.9.1

Weakness: CWE-390, CWE-693 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

References

https://github.com/mcdope/pam_usb/security/advisories/GHSA-pvrg-chgw-x42c x_refsource_CONFIRM
https://github.com/mcdope/pam_usb/issues/351 x_refsource_MISC
https://github.com/mcdope/pam_usb/issues/55 x_refsource_MISC