Out-of-bounds Write Affecting kernel package, versions <0:4.14.238-125.421.amzn1


Severity

Recommended
medium

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.04% (6th percentile)

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  • Snyk IDSNYK-AMZN201803-KERNEL-1726294
  • published27 Sept 2021
  • disclosed27 May 2021

Introduced: 27 May 2021

CVE-2021-33200  (opens in a new tab)
CWE-787  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2018.03 kernel to version 0:4.14.238-125.421.amzn1 or higher.
This issue was patched in ALAS-2021-1516.

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:2018.03 relevant fixed versions and status.

kernel/bpf/verifier.c in the Linux kernel through 5.12.7 enforces incorrect limits for pointer arithmetic operations, aka CID-bb01a1bba579. This can be abused to perform out-of-bounds reads and writes in kernel memory, leading to local privilege escalation to root. In particular, there is a corner case where the off reg causes a masking direction change, which then results in an incorrect final aux->alu_limit.

CVSS Scores

version 3.1