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CVE-2018-18281

Publication date 30 October 2018

Last updated 24 July 2024

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

7.8 · High

Score breakdown

Since Linux kernel version 3.2, the mremap() syscall performs TLB flushes after dropping pagetable locks. If a syscall such as ftruncate() removes entries from the pagetables of a task that is in the middle of mremap(), a stale TLB entry can remain for a short time that permits access to a physical page after it has been released back to the page allocator and reused. This is fixed in the following kernel versions: 4.9.135, 4.14.78, 4.18.16, 4.19.

From the Ubuntu Security Team

Jann Horn discovered that the mremap() system call in the Linux kernel did not properly flush the TLB when completing, potentially leaving access to a physical page after it has been released to the page allocator. A local attacker could use this to cause a denial of service (system crash), expose sensitive information, or possibly execute arbitrary code.

Status

Package Ubuntu Release Status
linux 20.04 LTS focal
Not affected
19.10 eoan
Not affected
19.04 disco
Not affected
18.10 cosmic
Fixed 4.18.0-12.13
18.04 LTS bionic
Fixed 4.15.0-44.47
16.04 LTS xenial
Fixed 4.4.0-142.168
14.04 LTS trusty
Fixed 3.13.0-165.215
linux-aws 20.04 LTS focal
Not affected
19.10 eoan
Not affected
19.04 disco
Not affected
18.10 cosmic
Fixed 4.18.0-1006.7
18.04 LTS bionic
Fixed 4.15.0-1032.34
16.04 LTS xenial
Fixed 4.4.0-1075.85
14.04 LTS trusty Ignored
linux-aws-5.0 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-aws-5.3 20.04 LTS focal Not in release
19.10 eoan Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-aws-hwe 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial
Fixed 4.15.0-1032.34~16.04.1
14.04 LTS trusty Not in release
linux-azure 20.04 LTS focal
Not affected
19.10 eoan
Not affected
19.04 disco
Not affected
18.10 cosmic
Fixed 4.18.0-1006.6
18.04 LTS bionic
Fixed 4.15.0-1037.39
16.04 LTS xenial
Fixed 4.15.0-1037.39~16.04.1
14.04 LTS trusty
Fixed 4.15.0-1037.39~14.04.2
linux-azure-4.15 20.04 LTS focal Not in release
19.10 eoan Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-azure-5.3 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-azure-5.4 20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-azure-edge 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic
Fixed 4.15.0-1037.39
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-euclid 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-flo 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-gcp 20.04 LTS focal
Not affected
19.10 eoan
Not affected
19.04 disco
Not affected
18.10 cosmic
Fixed 4.18.0-1004.5
18.04 LTS bionic
Fixed 4.15.0-1027.28
16.04 LTS xenial
Fixed 4.15.0-1027.28~16.04.1
14.04 LTS trusty Not in release
linux-gcp-4.15 20.04 LTS focal Not in release
19.10 eoan Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gcp-5.3 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gcp-edge 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic
Fixed 4.15.0-1027.28
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gke 20.04 LTS focal
Not affected
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-gke-4.15 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gke-5.0 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gke-5.3 20.04 LTS focal Not in release
19.10 eoan Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-goldfish 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-grouper 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-hwe 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial
Fixed 4.15.0-45.48~16.04.1
14.04 LTS trusty Not in release
linux-hwe-5.4 20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-hwe-edge 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial
Fixed 4.15.0-45.48~16.04.1
14.04 LTS trusty Not in release
linux-kvm 20.04 LTS focal
Not affected
19.10 eoan
Not affected
19.04 disco
Not affected
18.10 cosmic
Fixed 4.18.0-1005.5
18.04 LTS bionic
Fixed 4.15.0-1029.29
16.04 LTS xenial
Fixed 4.4.0-1040.46
14.04 LTS trusty Not in release
linux-lts-trusty 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-lts-utopic 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Ignored
linux-lts-vivid 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Ignored
linux-lts-wily 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Ignored
linux-lts-xenial 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Ignored
linux-maguro 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-mako 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-manta 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-oem 20.04 LTS focal Not in release
19.10 eoan
Not affected
19.04 disco
Not affected
18.10 cosmic
Fixed 4.15.0-1033.38
18.04 LTS bionic
Fixed 4.15.0-1033.38
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-oem-5.6 20.04 LTS focal
Not affected
19.10 eoan Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-oem-osp1 20.04 LTS focal Not in release
19.10 eoan
Not affected
19.04 disco
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-oracle 20.04 LTS focal
Not affected
19.10 eoan
Not affected
19.04 disco
Not affected
18.10 cosmic
Fixed 4.15.0-1008.10
18.04 LTS bionic
Fixed 4.15.0-1008.10
16.04 LTS xenial
Fixed 4.15.0-1008.10~16.04.1
14.04 LTS trusty Not in release
linux-oracle-5.0 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-oracle-5.3 20.04 LTS focal Not in release
19.10 eoan Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-raspi 20.04 LTS focal
Not affected
19.10 eoan Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-raspi-5.4 20.04 LTS focal Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-raspi2 20.04 LTS focal
Not affected
19.10 eoan
Not affected
19.04 disco
Not affected
18.10 cosmic
Fixed 4.18.0-1007.9
18.04 LTS bionic
Fixed 4.15.0-1031.33
16.04 LTS xenial
Fixed 4.4.0-1103.111
14.04 LTS trusty Not in release
linux-raspi2-5.3 20.04 LTS focal Not in release
19.10 eoan Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-riscv 20.04 LTS focal
Not affected
19.10 eoan Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-snapdragon 20.04 LTS focal Not in release
19.10 eoan Not in release
19.04 disco
Not affected
18.10 cosmic Not in release
18.04 LTS bionic
Fixed 4.15.0-1053.57
16.04 LTS xenial
Fixed 4.4.0-1107.112
14.04 LTS trusty Not in release

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
linux

Severity score breakdown

Parameter Value
Base score 7.8 · High
Attack vector Local
Attack complexity Low
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

Related Ubuntu Security Notices (USN)

    • USN-3880-2
    • Linux kernel (Trusty HWE) vulnerabilities
    • 4 February 2019
    • USN-3871-4
    • Linux kernel (HWE) vulnerabilities
    • 4 February 2019
    • USN-3871-1
    • Linux kernel vulnerabilities
    • 29 January 2019
    • USN-3871-5
    • Linux kernel (Azure) vulnerabilities
    • 7 February 2019
    • USN-3835-1
    • Linux kernel vulnerabilities
    • 3 December 2018
    • USN-3832-1
    • Linux kernel (AWS) vulnerabilities
    • 30 November 2018
    • USN-3880-1
    • Linux kernel vulnerabilities
    • 4 February 2019
    • USN-3871-3
    • Linux kernel (AWS, GCP, KVM, OEM, Raspberry Pi 2) vulnerabilities
    • 4 February 2019

Other references