Bug 2366848 (CVE-2025-37890) - CVE-2025-37890 kernel: net_sched: hfsc: Fix a UAF vulnerability in class with netem as child qdisc
Summary: CVE-2025-37890 kernel: net_sched: hfsc: Fix a UAF vulnerability in class with...
Keywords:
Status: NEW
Alias: CVE-2025-37890
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-05-16 14:01 UTC by OSIDB Bzimport
Modified: 2025-10-07 10:44 UTC (History)
6 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2025:12662 0 None None None 2025-08-04 09:20:52 UTC
Red Hat Product Errata RHSA-2025:12746 0 None None None 2025-08-04 16:18:36 UTC
Red Hat Product Errata RHSA-2025:12752 0 None None None 2025-08-04 16:51:31 UTC
Red Hat Product Errata RHSA-2025:12753 0 None None None 2025-08-04 16:23:24 UTC
Red Hat Product Errata RHSA-2025:13135 0 None None None 2025-08-06 07:51:35 UTC
Red Hat Product Errata RHSA-2025:14511 0 None None None 2025-08-25 14:13:44 UTC
Red Hat Product Errata RHSA-2025:14692 0 None None None 2025-08-27 00:23:15 UTC
Red Hat Product Errata RHSA-2025:14742 0 None None None 2025-08-27 10:39:45 UTC
Red Hat Product Errata RHSA-2025:14744 0 None None None 2025-08-27 11:39:52 UTC
Red Hat Product Errata RHSA-2025:14749 0 None None None 2025-08-27 13:19:58 UTC
Red Hat Product Errata RHSA-2025:15035 0 None None None 2025-09-02 06:52:52 UTC
Red Hat Product Errata RHSA-2025:16538 0 None None None 2025-09-24 00:27:28 UTC
Red Hat Product Errata RHSA-2025:16539 0 None None None 2025-09-24 00:18:07 UTC
Red Hat Product Errata RHSA-2025:16540 0 None None None 2025-09-24 00:25:14 UTC
Red Hat Product Errata RHSA-2025:16541 0 None None None 2025-09-24 00:19:23 UTC
Red Hat Product Errata RHSA-2025:16580 0 None None None 2025-09-24 12:48:59 UTC
Red Hat Product Errata RHSA-2025:16582 0 None None None 2025-09-24 13:00:14 UTC
Red Hat Product Errata RHSA-2025:16583 0 None None None 2025-09-24 13:03:04 UTC

Description OSIDB Bzimport 2025-05-16 14:01:18 UTC 
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/
Comment 1 Avinash Hanwate 2025-05-19 03:35:45 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025051617-CVE-2025-37890-437b@gregkh/T
Comment 15 errata-xmlrpc 2025-08-04 09:20:51 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2025:12662 https://access.redhat.com/errata/RHSA-2025:12662
Comment 16 errata-xmlrpc 2025-08-04 16:18:34 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2025:12746 https://access.redhat.com/errata/RHSA-2025:12746
Comment 17 errata-xmlrpc 2025-08-04 16:23:22 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2025:12753 https://access.redhat.com/errata/RHSA-2025:12753
Comment 18 errata-xmlrpc 2025-08-04 16:51:29 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2025:12752 https://access.redhat.com/errata/RHSA-2025:12752
Comment 19 errata-xmlrpc 2025-08-06 07:51:33 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Extended Update Support

Via RHSA-2025:13135 https://access.redhat.com/errata/RHSA-2025:13135
Comment 22 errata-xmlrpc 2025-08-25 14:13:42 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.8 Telecommunications Update Service

Via RHSA-2025:14511 https://access.redhat.com/errata/RHSA-2025:14511
Comment 23 errata-xmlrpc 2025-08-27 00:23:13 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.6 Telecommunications Update Service

Via RHSA-2025:14692 https://access.redhat.com/errata/RHSA-2025:14692
Comment 24 errata-xmlrpc 2025-08-27 10:39:44 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.2 Advanced Update Support

Via RHSA-2025:14742 https://access.redhat.com/errata/RHSA-2025:14742
Comment 25 errata-xmlrpc 2025-08-27 11:39:50 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions

Via RHSA-2025:14744 https://access.redhat.com/errata/RHSA-2025:14744
Comment 26 errata-xmlrpc 2025-08-27 13:19:56 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions

Via RHSA-2025:14749 https://access.redhat.com/errata/RHSA-2025:14749
Comment 27 errata-xmlrpc 2025-09-02 06:52:51 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On

Via RHSA-2025:15035 https://access.redhat.com/errata/RHSA-2025:15035
Comment 35 errata-xmlrpc 2025-09-24 00:18:06 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2025:16539 https://access.redhat.com/errata/RHSA-2025:16539
Comment 36 errata-xmlrpc 2025-09-24 00:19:21 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions

Via RHSA-2025:16541 https://access.redhat.com/errata/RHSA-2025:16541
Comment 37 errata-xmlrpc 2025-09-24 00:25:12 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Extended Update Support

Via RHSA-2025:16540 https://access.redhat.com/errata/RHSA-2025:16540
Comment 38 errata-xmlrpc 2025-09-24 00:27:27 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2025:16538 https://access.redhat.com/errata/RHSA-2025:16538
Comment 39 errata-xmlrpc 2025-09-24 12:48:58 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions

Via RHSA-2025:16580 https://access.redhat.com/errata/RHSA-2025:16580
Comment 40 errata-xmlrpc 2025-09-24 13:00:13 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2025:16582 https://access.redhat.com/errata/RHSA-2025:16582
Comment 41 errata-xmlrpc 2025-09-24 13:03:03 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions

Via RHSA-2025:16583 https://access.redhat.com/errata/RHSA-2025:16583
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