CVE intelligence and bounded remediation

CVE-2026-48986 — pam_usb provides hardware authentication for Linux using removable media

Medium CVSS 4.7

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.

Severity
Medium
CVSS
4.7 (3.1)
Published
2026-06-18
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-835

Affected products

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Matched remediation archetype

Resource exhaustion and denial of service

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Identify attacker-influenced work factors including input size, nesting, compression, fan-out, regex cost, allocation, recursion, retries, and connection lifetime.
  • Map per-request and shared CPU, memory, disk, descriptor, thread, queue, and downstream-service limits.
  • Determine whether authentication, tenancy, quotas, and rate controls apply before expensive processing begins.

Remediate safely

  • Bound input size, nesting, expansion, work, concurrency, queue depth, retries, and execution time before resource-intensive processing.
  • Release resources on every success, error, cancellation, and timeout path and use backpressure instead of unbounded buffering.
  • Update affected components and add small deterministic tests that assert resource ceilings rather than exhausting a host.

Authoritative sources

Complete CVE record and remediation plan

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