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CVE-2021-3748


A use-after-free vulnerability was found in the virtio-net device of QEMU. It could occur when the descriptor's address belongs to the non direct access region, due to num_buffers being set after the virtqueue elem has been unmapped. A malicious guest could use this flaw to crash QEMU, resulting in a denial of service condition, or potentially execute code on the host with the privileges of the QEMU process.


Security Impact Summary

This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 7.5, requiring local system access to exploit but requires specific conditions to be met without requiring user interaction . The vulnerability impacts confidentiality (data exposure), integrity (unauthorized modifications), and availability (service disruption) for affected systems. Impacting 6 products from qemu, from debian, from canonical and 3 others, organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2022, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.


Published

2022-03-23T20:15:09.893

Last Modified

2024-11-21T06:22:19.667

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 7.5 (HIGH)

CVSSv2 Vector

AV:L/AC:M/Au:N/C:C/I:C/A:C

  • Access Vector: LOCAL
  • Access Complexity: MEDIUM
  • Authentication: NONE
  • Confidentiality Impact: COMPLETE
  • Integrity Impact: COMPLETE
  • Availability Impact: COMPLETE
Exploitability Score

3.4

Impact Score

10.0

Weaknesses
  • Type: Secondary
    CWE-416
  • Type: Primary
    CWE-416

Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Application qemu qemu < 6.2.0 Yes
Operating System debian debian_linux 9.0 Yes
Operating System debian debian_linux 10.0 Yes
Operating System canonical ubuntu_linux 18.04 Yes
Operating System canonical ubuntu_linux 20.04 Yes
Operating System canonical ubuntu_linux 21.10 Yes
Operating System fedoraproject fedora 34 Yes
Operating System redhat enterprise_linux 8.0 Yes
Operating System redhat enterprise_linux_advanced_virtualization_eus 8.4 Yes

References

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For qemu's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.