UBUNTU-CVE-2020-29569

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    UBUNTU-CVE-2020-29569

    Published: 15 Dec 2020Last Modified: 9 Sept 2026
    Upstream:
    CVE-2020-29569
    Aliases:
    USN-4749-1
    USN-4750-1
    USN-4751-1

    Summary:

    Details: An issue was discovered in the Linux kernel through 5.10.1, as used with Xen through 4.14.x. The Linux kernel PV block backend expects the kernel thread handler to reset ring->xenblkd to NULL when stopped. However, the handler may not have time to run if the frontend quickly toggles between the states connect and disconnect. As a consequence, the block backend may re-use a pointer after it was freed. A misbehaving guest can trigger a dom0 crash by continuously connecting / disconnecting a block frontend. Privilege escalation and information leaks cannot be ruled out. This only affects systems with a Linux blkback.

    References: https://ubuntu.com/security/CVE-2020-29569, https://xenbits.xen.org/xsa/advisory-350.html, https://ubuntu.com/security/notices/USN-4749-1, https://ubuntu.com/security/notices/USN-4750-1, https://ubuntu.com/security/notices/USN-4751-1, https://ubuntu.com/security/notices/USN-4876-1, https://www.cve.org/CVERecord?id=CVE-2020-29569

    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 -4.4.0-1087.91

    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

    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
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