CVE-2025-21971

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Source
https://cve.org/CVERecord?id=CVE-2025-21971
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-21971.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2025-21971
Downstream
Related
Published
2025-04-01T15:47:04.448Z
Modified
2026-03-11T07:49:01.867762Z
Summary
net_sched: Prevent creation of classes with TC_H_ROOT
Details

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

netsched: Prevent creation of classes with TCH_ROOT

The function qdisctreereducebacklog() uses TCHROOT as a termination condition when traversing up the qdisc tree to update parent backlog counters. However, if a class is created with classid TCH_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 TCHROOT (0xFFFFFFFF) across all qdisc types, as suggested by Jamal.

Database specific 
{
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21971.json"
}
References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
066a3b5b2346febf9a655b444567b7138e3bb939
Fixed
e05d9938b1b0ac40b6054cc5fa0ccbd9afd5ed4c
Fixed
7a82fe67a9f4d7123d8e5ba8f0f0806c28695006
Fixed
003d92c91cdb5a64b25a9a74cb8543aac9a8bb48
Fixed
e5ee00607bbfc97ef1526ea95b6b2458ac9e7cb7
Fixed
78533c4a29ac3aeddce4b481770beaaa4f3bfb67
Fixed
5c3ca9cb48b51bd72bf76b8b05e24f3cd53db5e7
Fixed
94edfdfb9505ab608e86599d1d1e38c83816fc1c
Fixed
0c3057a5a04d07120b3d0ec9c79568fceb9c921e

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-21971.json"