# CVE-2026-47273

## Summary

- **CVE ID:** CVE-2026-47273
- **Severity:** MEDIUM
- **CVSS Score:** 6.5 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N)
- **CWE:** CWE-91
- **Published:** May 27, 2026
- **Last Modified:** May 28, 2026

## Description

pam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.9.0, pam_usb builds XPath expressions from user-supplied identifiers (PAM username, service name) and device-supplied identifiers (USB device serial, model, vendor) to query /etc/pamusb.conf. These identifiers were not validated for XPath metacharacters, allowing injection of arbitrary XPath predicates. This vulnerability is fixed in 0.9.0.

## Affected Products

- mcdope — pam_usb (< 0.9.0)

## References

- [CNA](https://github.com/mcdope/pam_usb/security/advisories/GHSA-vfj3-5h5v-6g93)
- [CNA](https://github.com/mcdope/pam_usb/pull/311)
- [CNA](https://github.com/mcdope/pam_usb/commit/721fed08a3596cb5b4671ad702f8fdc12dcc7420)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.27%
- **EPSS Percentile:** 19.5

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._