NULL Pointer Dereference Affecting kernel package, versions <0:4.14.177-139.254.amzn2


Severity

Recommended
high

Based on Amazon Linux security rating

    Threat Intelligence

    EPSS
    0.8% (83rd percentile)

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  • Snyk ID SNYK-AMZN2-KERNEL-1679795
  • published 27 Sep 2021
  • disclosed 22 May 2020

How to fix?

Upgrade Amazon-Linux:2 kernel to version 0:4.14.177-139.254.amzn2 or higher.
This issue was patched in ALAS2-2020-1425.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel package and not the kernel package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2 relevant fixed versions and status.

A NULL pointer dereference flaw was found in the Linux kernel's SELinux subsystem in versions before 5.7. This flaw occurs while importing the Commercial IP Security Option (CIPSO) protocol's category bitmap into the SELinux extensible bitmap via the' ebitmap_netlbl_import' routine. While processing the CIPSO restricted bitmap tag in the 'cipso_v4_parsetag_rbm' routine, it sets the security attribute to indicate that the category bitmap is present, even if it has not been allocated. This issue leads to a NULL pointer dereference issue while importing the same category bitmap into SELinux. This flaw allows a remote network user to crash the system kernel, resulting in a denial of service.

CVSS Scores

version 3.1
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NVD

5.9 medium
  • Attack Vector (AV)
    Network
  • Attack Complexity (AC)
    High
  • Privileges Required (PR)
    None
  • User Interaction (UI)
    None
  • Scope (S)
    Unchanged
  • Confidentiality (C)
    None
  • Integrity (I)
    None
  • Availability (A)
    High
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Red Hat

5.9 medium
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SUSE

5.9 medium