CVE Vulnerabilities

CVE-2017-18202

Use After Free

Published: Feb 27, 2018 | Modified: Sep 26, 2018
CVSS 3.x
7
HIGH
Source:
NVD
CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
6.9 MEDIUM
AV:L/AC:M/Au:N/C:C/I:C/A:C
RedHat/V2
RedHat/V3
6.7 IMPORTANT
CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H
Ubuntu

The __oom_reap_task_mm function in mm/oom_kill.c in the Linux kernel before 4.14.4 mishandles gather operations, which allows attackers to cause a denial of service (TLB entry leak or use-after-free) or possibly have unspecified other impact by triggering a copy_to_user call within a certain time window.

Weakness

Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

Affected Software

Name Vendor Start Version End Version
Linux_kernel Linux * *
Red Hat Enterprise Linux 7 RedHat kernel-alt-0:4.14.0-49.13.1.el7a *
Linux Ubuntu artful *
Linux Ubuntu upstream *
Linux-armadaxp Ubuntu upstream *
Linux-aws Ubuntu upstream *
Linux-azure Ubuntu esm-infra/xenial *
Linux-azure Ubuntu upstream *
Linux-azure Ubuntu xenial *
Linux-azure-edge Ubuntu upstream *
Linux-euclid Ubuntu upstream *
Linux-flo Ubuntu trusty *
Linux-flo Ubuntu upstream *
Linux-flo Ubuntu xenial *
Linux-gcp Ubuntu esm-infra/xenial *
Linux-gcp Ubuntu upstream *
Linux-gcp Ubuntu xenial *
Linux-gke Ubuntu upstream *
Linux-goldfish Ubuntu trusty *
Linux-goldfish Ubuntu upstream *
Linux-grouper Ubuntu trusty *
Linux-grouper Ubuntu upstream *
Linux-hwe Ubuntu esm-infra/xenial *
Linux-hwe Ubuntu upstream *
Linux-hwe Ubuntu xenial *
Linux-hwe-edge Ubuntu esm-infra/xenial *
Linux-hwe-edge Ubuntu upstream *
Linux-hwe-edge Ubuntu xenial *
Linux-kvm Ubuntu upstream *
Linux-linaro-omap Ubuntu upstream *
Linux-linaro-shared Ubuntu upstream *
Linux-linaro-vexpress Ubuntu upstream *
Linux-lts-quantal Ubuntu precise/esm *
Linux-lts-quantal Ubuntu upstream *
Linux-lts-raring Ubuntu precise/esm *
Linux-lts-raring Ubuntu upstream *
Linux-lts-saucy Ubuntu precise/esm *
Linux-lts-saucy Ubuntu upstream *
Linux-lts-trusty Ubuntu upstream *
Linux-lts-utopic Ubuntu trusty *
Linux-lts-utopic Ubuntu upstream *
Linux-lts-vivid Ubuntu trusty *
Linux-lts-vivid Ubuntu upstream *
Linux-lts-wily Ubuntu trusty *
Linux-lts-wily Ubuntu upstream *
Linux-lts-xenial Ubuntu upstream *
Linux-maguro Ubuntu trusty *
Linux-maguro Ubuntu upstream *
Linux-mako Ubuntu trusty *
Linux-mako Ubuntu upstream *
Linux-mako Ubuntu xenial *
Linux-manta Ubuntu trusty *
Linux-manta Ubuntu upstream *
Linux-oem Ubuntu upstream *
Linux-oem Ubuntu xenial *
Linux-qcm-msm Ubuntu upstream *
Linux-raspi2 Ubuntu artful *
Linux-raspi2 Ubuntu upstream *
Linux-snapdragon Ubuntu upstream *
Linux-ti-omap4 Ubuntu upstream *

Extended Description

The use of previously-freed memory can have any number of adverse consequences, ranging from the corruption of valid data to the execution of arbitrary code, depending on the instantiation and timing of the flaw. The simplest way data corruption may occur involves the system’s reuse of the freed memory. Use-after-free errors have two common and sometimes overlapping causes:

In this scenario, the memory in question is allocated to another pointer validly at some point after it has been freed. The original pointer to the freed memory is used again and points to somewhere within the new allocation. As the data is changed, it corrupts the validly used memory; this induces undefined behavior in the process. If the newly allocated data chances to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.

Potential Mitigations

References