CVE-2025-21971

UNKNOWN 0.0

net_sched: Prevent creation of classes with TC_H_ROOT

CVSS Score

0.0

EPSS Score

0.0%

EPSS Percentile

0th

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.

Vendor	linux
Product	linux
Ecosystems	Linux Kernel
Industries	Technology
Published	Apr 1, 2025
Last Updated	May 11, 2026

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Affected Versions

Linux / Linux

066a3b5b2346febf9a655b444567b7138e3bb939 < e05d9938b1b0ac40b6054cc5fa0ccbd9afd5ed4c 066a3b5b2346febf9a655b444567b7138e3bb939 < 7a82fe67a9f4d7123d8e5ba8f0f0806c28695006 066a3b5b2346febf9a655b444567b7138e3bb939 < 003d92c91cdb5a64b25a9a74cb8543aac9a8bb48 066a3b5b2346febf9a655b444567b7138e3bb939 < e5ee00607bbfc97ef1526ea95b6b2458ac9e7cb7 066a3b5b2346febf9a655b444567b7138e3bb939 < 78533c4a29ac3aeddce4b481770beaaa4f3bfb67 066a3b5b2346febf9a655b444567b7138e3bb939 < 5c3ca9cb48b51bd72bf76b8b05e24f3cd53db5e7 066a3b5b2346febf9a655b444567b7138e3bb939 < 94edfdfb9505ab608e86599d1d1e38c83816fc1c 066a3b5b2346febf9a655b444567b7138e3bb939 < 0c3057a5a04d07120b3d0ec9c79568fceb9c921e

Linux / Linux

2.6.25

References

NVD ↗ CVE.org ↗ EPSS Data ↗