QID 198333

Date Published: 2021-04-26

QID 198333: Ubuntu Security Notification for Linux kernel vulnerabilities (USN-4917-1)

The overlayfs implementation in the linux kernel did not properly validate the application of file system capabilities with respect to user namespaces
The shiftfs file system in the ubuntu linux kernel did not properly handle faults in copy_from_user() when passing through ioctls to an underlying file system
The bpf jit compiler for x86 in the linux kernel did not properly validate computation of branch displacements in some situations

A local attacker could use this to gain elevated privileges
(CVE-2021-3493)
A local attacker could use this to cause a denial of service (memory exhaustion) or execute arbitrary code
(CVE-2021-3492)
A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code
(CVE-2021-29154)

  • CVSS V3 rated as High - 7.8 severity.
  • CVSS V2 rated as High - 7.2 severity.
    • Solution
    Refer to Ubuntu advisory: USN-4917-1 for affected packages and patching details, or update with your package manager.
    Vendor References

    CVEs related to QID 198333

    CVE-2021-3493 | CVE-2021-3492 | CVE-2021-29154 |
    Software Advisories
    Advisory ID Software Component Link
    USN-4917-1 Ubuntu Linux URL Logo usn.ubuntu.com/4917-1
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