CVE-2026-48792 Details
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.
A vulnerability exists in pam_usb versions prior to 0.9.1, where the software improperly handles EACCES errors when accessing /dev/input/event* nodes. This oversight causes the function pusb_has_virtual_input_device() to incorrectly report that no virtual devices are available, even when permission issues prevent successful device detection. As a result, the authentication process may continue without properly verifying the presence of virtual devices, potentially leading to misconfigurations being overlooked. This issue is particularly relevant for administrators testing their pam_usb setup with the 'pamusb-check' tool, as it creates a false sense of security by not accurately reflecting the status of virtual input device detection.
Users can update to pam_usb version 0.9.1 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed May 27, 2026CISA-ADP
Assessed May 28, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/mcdope/pam_usb/issues/351 | [email protected] | ExploitIssue TrackingTechnical DescriptionVendor |
| https://github.com/mcdope/pam_usb/issues/55 | [email protected] | Issue TrackingVendor |
| https://github.com/mcdope/pam_usb/security/advisories/GHSA-pvrg-chgw-x42c | [email protected] | AdvisoryRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-390 | Detection of Error Condition Without Action | [email protected] |
| CWE-693 | Protection Mechanism Failure | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| pam_usb | <= 0.9.0 (semver) |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 27, 2026 | New CVE Received | [email protected] |