Advisory Published

USN-4887-1: Linux kernel vulnerabilities

First published: Tue Mar 23 2021(Updated: )

De4dCr0w of 360 Alpha Lab discovered that the BPF verifier in the Linux kernel did not properly handle mod32 destination register truncation when the source register was known to be 0. A local attacker could use this to expose sensitive information (kernel memory) or possibly execute arbitrary code. (CVE-2021-3444) Adam Nichols discovered that heap overflows existed in the iSCSI subsystem in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-27365) Piotr Krysiuk discovered that the BPF subsystem in the Linux kernel did not properly compute a speculative execution limit on pointer arithmetic in some situations. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2020-27171) Piotr Krysiuk discovered that the BPF subsystem in the Linux kernel did not properly apply speculative execution limits on some pointer types. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2020-27170) Adam Nichols discovered that the iSCSI subsystem in the Linux kernel did not properly restrict access to iSCSI transport handles. A local attacker could use this to cause a denial of service or expose sensitive information (kernel pointer addresses). (CVE-2021-27363) Adam Nichols discovered that an out-of-bounds read existed in the iSCSI subsystem in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or expose sensitive information (kernel memory). (CVE-2021-27364)

Affected SoftwareAffected VersionHow to fix
All of
ubuntu/linux-image-5.8.0-1019-raspi<5.8.0-1019.22
5.8.0-1019.22
Ubuntu=20.10
All of
ubuntu/linux-image-5.8.0-1019-raspi-nolpae<5.8.0-1019.22
5.8.0-1019.22
Ubuntu=20.10
All of
ubuntu/linux-image-5.8.0-1022-kvm<5.8.0-1022.24
5.8.0-1022.24
Ubuntu=20.10
All of
ubuntu/linux-image-5.8.0-1024-oracle<5.8.0-1024.25
5.8.0-1024.25
Ubuntu=20.10
All of
ubuntu/linux-image-5.8.0-1026-azure<5.8.0-1026.28
5.8.0-1026.28
Ubuntu=20.10
All of
ubuntu/linux-image-5.8.0-1026-gcp<5.8.0-1026.27
5.8.0-1026.27
Ubuntu=20.10
All of
ubuntu/linux-image-5.8.0-1027-aws<5.8.0-1027.29
5.8.0-1027.29
Ubuntu=20.10
All of
ubuntu/linux-image-5.8.0-48-generic<5.8.0-48.54
5.8.0-48.54
Ubuntu=20.10
All of
ubuntu/linux-image-5.8.0-48-generic-64k<5.8.0-48.54
5.8.0-48.54
Ubuntu=20.10
All of
ubuntu/linux-image-5.8.0-48-generic-lpae<5.8.0-48.54
5.8.0-48.54
Ubuntu=20.10
All of
ubuntu/linux-image-5.8.0-48-lowlatency<5.8.0-48.54
5.8.0-48.54
Ubuntu=20.10
All of
ubuntu/linux-image-aws<5.8.0.1027.29
5.8.0.1027.29
Ubuntu=20.10
All of
ubuntu/linux-image-azure<5.8.0.1026.26
5.8.0.1026.26
Ubuntu=20.10
All of
ubuntu/linux-image-gcp<5.8.0.1026.26
5.8.0.1026.26
Ubuntu=20.10
All of
ubuntu/linux-image-generic<5.8.0.48.53
5.8.0.48.53
Ubuntu=20.10
All of
ubuntu/linux-image-generic-64k<5.8.0.48.53
5.8.0.48.53
Ubuntu=20.10
All of
ubuntu/linux-image-generic-lpae<5.8.0.48.53
5.8.0.48.53
Ubuntu=20.10
All of
ubuntu/linux-image-gke<5.8.0.1026.26
5.8.0.1026.26
Ubuntu=20.10
All of
ubuntu/linux-image-kvm<5.8.0.1022.24
5.8.0.1022.24
Ubuntu=20.10
All of
ubuntu/linux-image-lowlatency<5.8.0.48.53
5.8.0.48.53
Ubuntu=20.10
All of
ubuntu/linux-image-oem-20.04<5.8.0.48.53
5.8.0.48.53
Ubuntu=20.10
All of
ubuntu/linux-image-oracle<5.8.0.1024.23
5.8.0.1024.23
Ubuntu=20.10
All of
ubuntu/linux-image-raspi<5.8.0.1019.22
5.8.0.1019.22
Ubuntu=20.10
All of
ubuntu/linux-image-raspi-nolpae<5.8.0.1019.22
5.8.0.1019.22
Ubuntu=20.10
All of
ubuntu/linux-image-virtual<5.8.0.48.53
5.8.0.48.53
Ubuntu=20.10
All of
ubuntu/linux-image-5.10.0-1019-oem<5.10.0-1019.20
5.10.0-1019.20
Ubuntu=20.04
All of
ubuntu/linux-image-5.4.0-1012-gkeop<5.4.0-1012.13
5.4.0-1012.13
Ubuntu=20.04
All of
ubuntu/linux-image-5.4.0-1032-raspi<5.4.0-1032.35
5.4.0-1032.35
Ubuntu=20.04
All of
ubuntu/linux-image-5.4.0-1036-kvm<5.4.0-1036.37
5.4.0-1036.37
Ubuntu=20.04
All of
ubuntu/linux-image-5.4.0-1040-gcp<5.4.0-1040.43
5.4.0-1040.43
Ubuntu=20.04
All of
ubuntu/linux-image-5.4.0-1041-aws<5.4.0-1041.43
5.4.0-1041.43
Ubuntu=20.04
All of
ubuntu/linux-image-5.4.0-1041-oracle<5.4.0-1041.44
5.4.0-1041.44
Ubuntu=20.04
All of
ubuntu/linux-image-5.4.0-1043-azure<5.4.0-1043.45
5.4.0-1043.45
Ubuntu=20.04
All of
ubuntu/linux-image-5.4.0-70-generic<5.4.0-70.78
5.4.0-70.78
Ubuntu=20.04
All of
ubuntu/linux-image-5.4.0-70-generic-lpae<5.4.0-70.78
5.4.0-70.78
Ubuntu=20.04
All of
ubuntu/linux-image-5.4.0-70-lowlatency<5.4.0-70.78
5.4.0-70.78
Ubuntu=20.04
All of
ubuntu/linux-image-5.6.0-1052-oem<5.6.0-1052.56
5.6.0-1052.56
Ubuntu=20.04
All of
ubuntu/linux-image-5.8.0-48-generic<5.8.0-48.54~20.04.1
5.8.0-48.54~20.04.1
Ubuntu=20.04
All of
ubuntu/linux-image-5.8.0-48-generic-64k<5.8.0-48.54~20.04.1
5.8.0-48.54~20.04.1
Ubuntu=20.04
All of
ubuntu/linux-image-5.8.0-48-generic-lpae<5.8.0-48.54~20.04.1
5.8.0-48.54~20.04.1
Ubuntu=20.04
All of
ubuntu/linux-image-5.8.0-48-lowlatency<5.8.0-48.54~20.04.1
5.8.0-48.54~20.04.1
Ubuntu=20.04
All of
ubuntu/linux-image-aws<5.4.0.1041.42
5.4.0.1041.42
Ubuntu=20.04
All of
ubuntu/linux-image-azure<5.4.0.1043.41
5.4.0.1043.41
Ubuntu=20.04
All of
ubuntu/linux-image-gcp<5.4.0.1040.49
5.4.0.1040.49
Ubuntu=20.04
All of
ubuntu/linux-image-generic<5.4.0.70.73
5.4.0.70.73
Ubuntu=20.04
All of
ubuntu/linux-image-generic-64k-hwe-20.04<5.8.0.48.54~20.04.32
5.8.0.48.54~20.04.32
Ubuntu=20.04
All of
ubuntu/linux-image-generic-hwe-20.04<5.8.0.48.54~20.04.32
5.8.0.48.54~20.04.32
Ubuntu=20.04
All of
ubuntu/linux-image-generic-lpae<5.4.0.70.73
5.4.0.70.73
Ubuntu=20.04
All of
ubuntu/linux-image-generic-lpae-hwe-20.04<5.8.0.48.54~20.04.32
5.8.0.48.54~20.04.32
Ubuntu=20.04
All of
ubuntu/linux-image-gkeop<5.4.0.1012.15
5.4.0.1012.15
Ubuntu=20.04
All of
ubuntu/linux-image-gkeop-5.4<5.4.0.1012.15
5.4.0.1012.15
Ubuntu=20.04
All of
ubuntu/linux-image-kvm<5.4.0.1036.34
5.4.0.1036.34
Ubuntu=20.04
All of
ubuntu/linux-image-lowlatency<5.4.0.70.73
5.4.0.70.73
Ubuntu=20.04
All of
ubuntu/linux-image-lowlatency-hwe-20.04<5.8.0.48.54~20.04.32
5.8.0.48.54~20.04.32
Ubuntu=20.04
All of
ubuntu/linux-image-oem<5.4.0.70.73
5.4.0.70.73
Ubuntu=20.04
All of
ubuntu/linux-image-oem-20.04<5.6.0.1052.48
5.6.0.1052.48
Ubuntu=20.04
All of
ubuntu/linux-image-oem-20.04b<5.10.0.1019.20
5.10.0.1019.20
Ubuntu=20.04
All of
ubuntu/linux-image-oem-osp1<5.4.0.70.73
5.4.0.70.73
Ubuntu=20.04
All of
ubuntu/linux-image-oracle<5.4.0.1041.38
5.4.0.1041.38
Ubuntu=20.04
All of
ubuntu/linux-image-raspi<5.4.0.1032.67
5.4.0.1032.67
Ubuntu=20.04
All of
ubuntu/linux-image-raspi2<5.4.0.1032.67
5.4.0.1032.67
Ubuntu=20.04
All of
ubuntu/linux-image-virtual<5.4.0.70.73
5.4.0.70.73
Ubuntu=20.04
All of
ubuntu/linux-image-virtual-hwe-20.04<5.8.0.48.54~20.04.32
5.8.0.48.54~20.04.32
Ubuntu=20.04
All of
ubuntu/linux-image-5.3.0-1038-raspi2<5.3.0-1038.40
5.3.0-1038.40
Ubuntu=18.04
All of
ubuntu/linux-image-5.3.0-1041-gke<5.3.0-1041.44
5.3.0-1041.44
Ubuntu=18.04
All of
ubuntu/linux-image-5.3.0-72-generic<5.3.0-72.68
5.3.0-72.68
Ubuntu=18.04
All of
ubuntu/linux-image-5.3.0-72-lowlatency<5.3.0-72.68
5.3.0-72.68
Ubuntu=18.04
All of
ubuntu/linux-image-5.4.0-1012-gkeop<5.4.0-1012.13~18.04.1
5.4.0-1012.13~18.04.1
Ubuntu=18.04
All of
ubuntu/linux-image-5.4.0-1032-raspi<5.4.0-1032.35~18.04.1
5.4.0-1032.35~18.04.1
Ubuntu=18.04
All of
ubuntu/linux-image-5.4.0-1039-gke<5.4.0-1039.41~18.04.1
5.4.0-1039.41~18.04.1
Ubuntu=18.04
All of
ubuntu/linux-image-5.4.0-1040-gcp<5.4.0-1040.43~18.04.1
5.4.0-1040.43~18.04.1
Ubuntu=18.04
All of
ubuntu/linux-image-5.4.0-1041-aws<5.4.0-1041.43~18.04.1
5.4.0-1041.43~18.04.1
Ubuntu=18.04
All of
ubuntu/linux-image-5.4.0-1041-oracle<5.4.0-1041.44~18.04.1
5.4.0-1041.44~18.04.1
Ubuntu=18.04
All of
ubuntu/linux-image-5.4.0-1043-azure<5.4.0-1043.45~18.04.1
5.4.0-1043.45~18.04.1
Ubuntu=18.04
All of
ubuntu/linux-image-5.4.0-70-generic<5.4.0-70.78~18.04.1
5.4.0-70.78~18.04.1
Ubuntu=18.04
All of
ubuntu/linux-image-5.4.0-70-generic-lpae<5.4.0-70.78~18.04.1
5.4.0-70.78~18.04.1
Ubuntu=18.04
All of
ubuntu/linux-image-5.4.0-70-lowlatency<5.4.0-70.78~18.04.1
5.4.0-70.78~18.04.1
Ubuntu=18.04
All of
ubuntu/linux-image-aws<5.4.0.1041.24
5.4.0.1041.24
Ubuntu=18.04
All of
ubuntu/linux-image-azure<5.4.0.1043.23
5.4.0.1043.23
Ubuntu=18.04
All of
ubuntu/linux-image-gcp<5.4.0.1040.27
5.4.0.1040.27
Ubuntu=18.04
All of
ubuntu/linux-image-generic-hwe-18.04<5.4.0.70.78~18.04.63
5.4.0.70.78~18.04.63
Ubuntu=18.04
All of
ubuntu/linux-image-generic-lpae-hwe-18.04<5.4.0.70.78~18.04.63
5.4.0.70.78~18.04.63
Ubuntu=18.04
All of
ubuntu/linux-image-gke-5.3<5.3.0.1041.24
5.3.0.1041.24
Ubuntu=18.04
All of
ubuntu/linux-image-gke-5.4<5.4.0.1039.41~18.04.6
5.4.0.1039.41~18.04.6
Ubuntu=18.04
All of
ubuntu/linux-image-gkeop-5.3<5.3.0.72.129
5.3.0.72.129
Ubuntu=18.04
All of
ubuntu/linux-image-gkeop-5.4<5.4.0.1012.13~18.04.13
5.4.0.1012.13~18.04.13
Ubuntu=18.04
All of
ubuntu/linux-image-lowlatency-hwe-18.04<5.4.0.70.78~18.04.63
5.4.0.70.78~18.04.63
Ubuntu=18.04
All of
ubuntu/linux-image-oem<5.4.0.70.78~18.04.63
5.4.0.70.78~18.04.63
Ubuntu=18.04
All of
ubuntu/linux-image-oem-osp1<5.4.0.70.78~18.04.63
5.4.0.70.78~18.04.63
Ubuntu=18.04
All of
ubuntu/linux-image-oracle<5.4.0.1041.44~18.04.23
5.4.0.1041.44~18.04.23
Ubuntu=18.04
All of
ubuntu/linux-image-raspi-hwe-18.04<5.4.0.1032.34
5.4.0.1032.34
Ubuntu=18.04
All of
ubuntu/linux-image-raspi2-hwe-18.04<5.3.0.1038.27
5.3.0.1038.27
Ubuntu=18.04
All of
ubuntu/linux-image-snapdragon-hwe-18.04<5.4.0.70.78~18.04.63
5.4.0.70.78~18.04.63
Ubuntu=18.04
All of
ubuntu/linux-image-virtual-hwe-18.04<5.4.0.70.78~18.04.63
5.4.0.70.78~18.04.63
Ubuntu=18.04

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Reference Links

Child vulnerabilities

(Contains the following vulnerabilities)

Frequently Asked Questions

  • What is the severity of USN-4887-1?

    USN-4887-1 is classified as a medium severity vulnerability affecting the BPF verifier in the Linux kernel.

  • How do I fix USN-4887-1?

    To fix USN-4887-1, upgrade to the patched kernel version provided in the advisory.

  • Which systems are affected by USN-4887-1?

    USN-4887-1 affects Ubuntu 20.10 with specific kernel versions listed in the advisory.

  • What are the risks associated with USN-4887-1?

    The risks include potential exposure of sensitive kernel memory to local attackers.

  • Who discovered the vulnerability addressed in USN-4887-1?

    The vulnerability in USN-4887-1 was discovered by De4dCr0w of 360 Alpha Lab.

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