QID 198325

Date Published: 2021-04-21

QID 198325: Ubuntu Security Notification for Linux kernel vulnerabilities (USN-4909-1)

The bpf implementation in the linux kernel did not properly validate attributes in the getsockopt bpf hook
The xen paravirtualization backend in the linux kernel did not properly propagate errors to frontend drivers in some situations
Multiple xen backends in the linux kernel did not properly handle certain error conditions under paravirtualization
The network block device (nbd) driver in the linux kernel contained a use-after-free vulnerability during device setup

A local attacker could possibly use this to cause a denial of service (system crash) (CVE-2021-20194)
An attacker in a guest VM could possibly use this to cause a denial of service (host domain crash) (CVE-2021-26930)
An attacker in a guest VM could possibly use this to cause a denial of service (host domain crash) (CVE-2021-26931)
A local attacker with access to the nbd device could use this to cause a denial of service (system crash) or possibly execute arbitrary code (CVE-2021-3348)

  • CVSS V3 rated as High - 7.8 severity.
  • CVSS V2 rated as Medium - 4.6 severity.
    • Solution
    Refer to Ubuntu advisory: USN-4909-1 for affected packages and patching details, or update with your package manager.
    Vendor References

    CVEs related to QID 198325

    CVE-2021-20194 | CVE-2021-3348 | CVE-2021-26930 | CVE-2021-26931 |
    Software Advisories
    Advisory ID Software Component Link
    USN-4909-1 Ubuntu Linux URL Logo usn.ubuntu.com/4909-1
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