CVE intelligence and bounded remediation

CVE-2021-3930 — An off-by-one error was found in the SCSI device emulation in QEMU

Medium CVSS 6.5

An off-by-one error was found in the SCSI device emulation in QEMU. It could occur while processing MODE SELECT commands in mode_sense_page() if the 'page' argument was set to MODE_PAGE_ALLS (0x3f). A malicious guest could use this flaw to potentially crash QEMU, resulting in a denial of service condition.

Severity
Medium
CVSS
6.5 (3.1)
Published
2022-02-18
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-193

Affected products

  • qemu / qemu
  • redhat / codeready_linux_builder / 8.0
  • redhat / codeready_linux_builder_for_ibm_z_systems / 8.0
  • redhat / codeready_linux_builder_for_power_little_endian / 8.0
  • redhat / openstack / 10
  • redhat / openstack / 13

Showing 6 representative product identities from 12 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

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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