UBUNTU-CVE-2021-4001

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    UBUNTU-CVE-2021-4001

    Published: 25 Nov 2021Last Modified: 22 Apr 2026
    Upstream:
    CVE-2021-4001
    Aliases:
    USN-5207-1
    USN-5265-1
    USN-5278-1

    Summary:

    Details: A race condition was found in the Linux kernel's ebpf verifier between bpf_map_update_elem and bpf_map_freeze due to a missing lock in kernel/bpf/syscall.c. In this flaw, a local user with a special privilege (cap_sys_admin or cap_bpf) can modify the frozen mapped address space. This flaw affects kernel versions prior to 5.16 rc2.

    References: https://ubuntu.com/security/CVE-2021-4001, https://git.kernel.org/linus/353050be4c19e102178ccc05988101887c25ae53, https://ubuntu.com/security/notices/USN-5207-1, https://ubuntu.com/security/notices/USN-5265-1, https://ubuntu.com/security/notices/USN-5278-1, https://ubuntu.com/security/notices/USN-6417-1, https://www.cve.org/CVERecord?id=CVE-2021-4001

    Affected packages

    Package

    Name: linux-hwe-edge

    Purl: pkg:deb/ubuntu/[email protected]~16.04.1?arch=source&distro=xenial

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    4.8.0-28.30~16.04.1
    4.8.0-30.32~16.04.1
    4.8.0-32.34~16.04.1
    4.8.0-34.36~16.04.1

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    UBUNTU-CVE-2021-4001 | CVE-DB