Use After Free Affecting kernel-rt-kvm package, versions <0:3.10.0-1160.rt56.1131.el7


Severity

high

    Threat Intelligence

    EPSS
    0.05% (15th percentile)

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  • Snyk ID SNYK-CENTOS7-KERNELRTKVM-2175256
  • published 26 Jul 2021
  • disclosed 25 Nov 2019

How to fix?

Upgrade Centos:7 kernel-rt-kvm to version 0:3.10.0-1160.rt56.1131.el7 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-kvm package and not the kernel-rt-kvm package as distributed by Centos. See How to fix? for Centos:7 relevant fixed versions and status.

There is a use-after-free in kernel versions before 5.5 due to a race condition between the release of ptp_clock and cdev while resource deallocation. When a (high privileged) process allocates a ptp device file (like /dev/ptpX) and voluntarily goes to sleep. During this time if the underlying device is removed, it can cause an exploitable condition as the process wakes up to terminate and clean all attached files. The system crashes due to the cdev structure being invalid (as already freed) which is pointed to by the inode.

CVSS Scores

version 3.1
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Snyk

6.5 high
  • Attack Vector (AV)
    Local
  • Attack Complexity (AC)
    Low
  • Privileges Required (PR)
    High
  • User Interaction (UI)
    Required
  • Scope (S)
    Unchanged
  • Confidentiality (C)
    High
  • Integrity (I)
    High
  • Availability (A)
    High
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NVD

6.4 medium
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SUSE

6.4 medium
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Red Hat

6.5 medium