UBUNTU-CVE-2021-3493

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    UBUNTU-CVE-2021-3493

    Published: 15 Apr 2021Last Modified: 9 Sept 2026
    Upstream:
    CVE-2021-3493

    Summary:

    Details: The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges.

    References: https://ubuntu.com/security/CVE-2021-3493, https://ubuntu.com/security/notices/USN-4915-1, https://ubuntu.com/security/notices/USN-4916-1, https://ubuntu.com/security/notices/USN-4917-1, https://www.openwall.com/lists/oss-security/2021/04/16/1, https://www.cve.org/CVERecord?id=CVE-2021-3493, https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Affected packages

    Package

    Name: linux-aws

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

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -4.4.0-1091.95

    Affected versions

    4.4.0-1002.2
    4.4.0-1003.3
    4.4.0-1005.5
    4.4.0-1006.6
    4.4.0-1009.9
    4.4.0-1010.10
    4.4.0-1011.11
    4.4.0-1012.12
    4.4.0-1014.14
    4.4.0-1016.16
    4.4.0-1017.17
    4.4.0-1019.19
    4.4.0-1022.22
    4.4.0-1023.23
    4.4.0-1024.25
    4.4.0-1025.26
    4.4.0-1027.30
    4.4.0-1028.31
    4.4.0-1029.32
    4.4.0-1031.34
    4.4.0-1032.35
    4.4.0-1034.37
    4.4.0-1036.39
    4.4.0-1037.40
    4.4.0-1038.41
    4.4.0-1039.42
    4.4.0-1040.43
    4.4.0-1042.45
    4.4.0-1044.47
    4.4.0-1045.48
    4.4.0-1046.50
    4.4.0-1048.52
    4.4.0-1050.54
    4.4.0-1052.56
    4.4.0-1054.58
    4.4.0-1055.59
    4.4.0-1056.60
    4.4.0-1058.62
    4.4.0-1059.63
    4.4.0-1060.64
    4.4.0-1061.65
    4.4.0-1062.66
    4.4.0-1064.68
    4.4.0-1065.69
    4.4.0-1066.70
    4.4.0-1067.71
    4.4.0-1073.77
    4.4.0-1074.78
    4.4.0-1075.79
    4.4.0-1076.80
    4.4.0-1077.81
    4.4.0-1078.82
    4.4.0-1081.85
    4.4.0-1082.86
    4.4.0-1083.87
    4.4.0-1085.89
    4.4.0-1086.90
    4.4.0-1087.91
    4.4.0-1088.92
    4.4.0-1090.94

    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-2021-3493 | CVE-DB