Vulnerability Description
pam_usb provides hardware authentication for Linux using removable media. In pam_usb 0.9.1 and earlier, usb_get_process_parent_id() can cause an infinite loop DoS because it does not initialize *ppid on failure. In pusb_local_login(), the same variable is reused as input and output in a process-tree while loop; if /proc/<pid>/stat cannot be read (for example, when an ancestor process exits during authentication), the PID is not updated and the loop does not terminate. This hangs the authenticating process (such as sudo, sshd, or login) until it is forcibly terminated. This issue has been fixed in version 0.9.2.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/mcdope/pam_usb/releases/tag/0.9.2
- https://github.com/mcdope/pam_usb/security/advisories/GHSA-h28h-9hc3-v595
FAQ
What is CVE-2026-48986?
CVE-2026-48986 is a vulnerability with a CVSS score of 4.7 (MEDIUM). pam_usb provides hardware authentication for Linux using removable media. In pam_usb 0.9.1 and earlier, usb_get_process_parent_id() can cause an infinite loop DoS because it does not initialize *ppid ...
How severe is CVE-2026-48986?
CVE-2026-48986 has been rated MEDIUM with a CVSS base score of 4.7/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-48986?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.