Use After Free Affecting kernel-tools-devel package, versions <0:4.14.238-182.421.amzn2


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.04% (13th percentile)

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  • Snyk IDSNYK-AMZN2-KERNELTOOLSDEVEL-8539729
  • published20 Dec 2024
  • disclosed21 May 2024

Introduced: 21 May 2024

CVE-2021-47259  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2 kernel-tools-devel to version 0:4.14.238-182.421.amzn2 or higher.
This issue was patched in ALAS2-2021-1685.

NVD Description

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

In the Linux kernel, the following vulnerability has been resolved:

NFS: Fix use-after-free in nfs4_init_client()

KASAN reports a use-after-free when attempting to mount two different exports through two different NICs that belong to the same server.

Olga was able to hit this with kernels starting somewhere between 5.7 and 5.10, but I traced the patch that introduced the clear_bit() call to 4.13. So something must have changed in the refcounting of the clp pointer to make this call to nfs_put_client() the very last one.

CVSS Scores

version 3.1