UBUNTU-CVE-2021-33909

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    UBUNTU-CVE-2021-33909

    Published: 20 Jul 2021Last Modified: 9 Sept 2026
    Upstream:
    CVE-2021-33909
    Aliases:
    USN-5014-1
    USN-5015-1
    USN-5016-1

    Summary:

    Details: fs/seq_file.c in the Linux kernel 3.16 through 5.13.x before 5.13.4 does not properly restrict seq buffer allocations, leading to an integer overflow, an Out-of-bounds Write, and escalation to root by an unprivileged user, aka CID-8cae8cd89f05.

    References: https://ubuntu.com/security/CVE-2021-33909, https://www.qualys.com/2021/07/20/cve-2021-33909/sequoia-local-privilege-escalation-linux.txt, https://www.openwall.com/lists/oss-security/2021/07/20/1, https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8cae8cd89f05f6de223d63e6d15e31c8ba9cf53b, https://ubuntu.com/security/notices/USN-5018-1, https://ubuntu.com/security/notices/USN-5017-1, https://ubuntu.com/security/notices/USN-5016-1, https://ubuntu.com/security/notices/USN-5015-1, https://ubuntu.com/security/notices/USN-5014-1, https://www.cve.org/CVERecord?id=CVE-2021-33909

    Affected packages

    Package

    Name: linux

    Purl: pkg:deb/ubuntu/linux?arch=source&distro=trusty%2Fesm

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -3.13.0-186.237

    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-2021-33909 | CVE-DB