NULL Pointer Dereference Affecting kernel-rt-kvm package, versions *


Severity

Recommended
low

Based on CentOS security rating.

Threat Intelligence

EPSS
0.04% (13th percentile)

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  • Snyk IDSNYK-CENTOS7-KERNELRTKVM-8878491
  • published28 Feb 2025
  • disclosed19 Jan 2025

Introduced: 19 Jan 2025

CVE-2025-21638  (opens in a new tab)
CWE-476  (opens in a new tab)

How to fix?

There is no fixed version for Centos:7 kernel-rt-kvm.

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.

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

sctp: sysctl: auth_enable: avoid using current->nsproxy

As mentioned in a previous commit of this series, using the 'net' structure via 'current' is not recommended for different reasons:

  • Inconsistency: getting info from the reader's/writer's netns vs only from the opener's netns.

  • current->nsproxy can be NULL in some cases, resulting in an 'Oops' (null-ptr-deref), e.g. when the current task is exiting, as spotted by syzbot [1] using acct(2).

The 'net' structure can be obtained from the table->data using container_of().

Note that table->data could also be used directly, but that would increase the size of this fix, while 'sctp.ctl_sock' still needs to be retrieved from 'net' structure.

CVSS Scores

version 3.1