In the Linux kernel, the following vulnerability has been resolved: net_sched: Prevent creation of classes with TC_H_ROOT The function qdisc_tree_reduce_backlog() uses TC_H_ROOT as a termination condition when traversing up the qdisc tree to update parent backlog counters. However, if a class is created with classid TC_H_ROOT, the traversal terminates prematurely at this class instead of reaching the actual root qdisc, causing parent statistics to be incorrectly maintained. In case of DRR, this could lead to a crash as reported by Mingi Cho. Prevent the creation of any Qdisc class with classid TC_H_ROOT (0xFFFFFFFF) across all qdisc types, as suggested by Jamal.
History

Fri, 23 May 2025 02:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-703

Thu, 10 Apr 2025 13:15:00 +0000


Wed, 02 Apr 2025 14:00:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


Tue, 01 Apr 2025 16:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: net_sched: Prevent creation of classes with TC_H_ROOT The function qdisc_tree_reduce_backlog() uses TC_H_ROOT as a termination condition when traversing up the qdisc tree to update parent backlog counters. However, if a class is created with classid TC_H_ROOT, the traversal terminates prematurely at this class instead of reaching the actual root qdisc, causing parent statistics to be incorrectly maintained. In case of DRR, this could lead to a crash as reported by Mingi Cho. Prevent the creation of any Qdisc class with classid TC_H_ROOT (0xFFFFFFFF) across all qdisc types, as suggested by Jamal.
Title net_sched: Prevent creation of classes with TC_H_ROOT
References

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2025-04-01T15:47:04.448Z

Updated: 2025-05-04T07:26:09.021Z

Reserved: 2024-12-29T08:45:45.797Z

Link: CVE-2025-21971

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-04-01T16:15:28.440

Modified: 2025-04-10T13:15:48.453

Link: CVE-2025-21971

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-04-01T00:00:00Z

Links: CVE-2025-21971 - Bugzilla