What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 4.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-27 · updated 2026-10-26
• Weakness: CWE-390

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

• mcdope pam_usb: before 0.9.1

References

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

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