QID 198326

Date Published: 2021-04-21

QID 198326: Ubuntu Security Notification for Linux kernel vulnerabilities (USN-4910-1)

The sockopt bpf hooks in the linux kernel could allow a user space program to probe for valid kernel addresses
The bpf verifier in the linux kernel did not properly handle signed add32 and sub integer overflows
The priority inheritance futex implementation in the linux kernel contained a race condition, leading to a use-after-free vulnerability
The network block device (nbd) driver in the linux kernel contained a use-after-free vulnerability during device setup
The nfs implementation in the linux kernel did not properly prevent access outside of an nfs export that is a subdirectory of a file system

A local attacker could use this to ease exploitation of another kernel vulnerability (CVE-2021-20239)
A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code (CVE-2021-20268)
A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code (CVE-2021-3347)
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)
An attacker could possibly use this to bypass NFS access restrictions (CVE-2021-3178)

  • CVSS V3 rated as High - 7.8 severity.
  • CVSS V2 rated as High - 7.2 severity.
    • Solution
    Refer to Ubuntu advisory: USN-4910-1 for affected packages and patching details, or update with your package manager.
    Vendor References

    CVEs related to QID 198326

    CVE-2021-20268 | CVE-2021-3178 | CVE-2021-3347 | CVE-2021-3348 | CVE-2021-20239 |
    Software Advisories
    Advisory ID Software Component Link
    USN-4910-1 Ubuntu Linux URL Logo usn.ubuntu.com/4910-1
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