UBUNTU-CVE-2021-34556

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    UBUNTU-CVE-2021-34556

    Published: 2 Aug 2021Last Modified: 9 Sept 2026
    Upstream:
    CVE-2021-34556
    Aliases:
    USN-5092-1
    USN-5092-2
    USN-5096-1

    Summary:

    Details: In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because the protection mechanism neglects the possibility of uninitialized memory locations on the BPF stack.

    References: https://ubuntu.com/security/CVE-2021-34556, https://www.openwall.com/lists/oss-security/2021/08/01/3, https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/patch/?id=f5e81d1117501546b7be050c5fbafa6efd2c722c, https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/patch/?id=2039f26f3aca5b0e419b98f65dd36481337b86ee, https://ubuntu.com/security/notices/USN-5092-1, https://ubuntu.com/security/notices/USN-5092-2, https://ubuntu.com/security/notices/USN-5096-1, https://ubuntu.com/security/notices/USN-5115-1, https://ubuntu.com/security/notices/USN-5137-1, https://ubuntu.com/security/notices/USN-5137-2, https://www.cve.org/CVERecord?id=CVE-2021-34556

    Affected packages

    Package

    Name: linux

    Purl: pkg:deb/ubuntu/linux?arch=source&distro=esm-infra-legacy%2Ftrusty

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    3.11.0-12.19

    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-2021-34556 | CVE-DB