Use After Free Affecting kernel-64k-debug package, versions *


Severity

Recommended
0.0
high
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.05% (16th percentile)

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  • Snyk IDSNYK-RHEL9-KERNEL64KDEBUG-10184069
  • published19 May 2025
  • disclosed16 May 2025

Introduced: 16 May 2025

CVE-2025-37890  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:9 kernel-64k-debug.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-64k-debug package and not the kernel-64k-debug package as distributed by RHEL. See How to fix? for RHEL:9 relevant fixed versions and status.

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

net_sched: hfsc: Fix a UAF vulnerability in class with netem as child qdisc

As described in Gerrard's report [1], we have a UAF case when an hfsc class has a netem child qdisc. The crux of the issue is that hfsc is assuming that checking for cl->qdisc->q.qlen == 0 guarantees that it hasn't inserted the class in the vttree or eltree (which is not true for the netem duplicate case).

This patch checks the n_active class variable to make sure that the code won't insert the class in the vttree or eltree twice, catering for the reentrant case.

[1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/

CVSS Base Scores

version 3.1