Vulnerability-Lookup

GHSA-37V5-VMQ6-F37G

Vulnerability from github – Published: 2025-04-01 18:30 – Updated: 2025-11-03 21:33

Details

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.

Severity

5.5 (Medium)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2025-21971"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-835"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-04-01T16:15:28Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet_sched: Prevent creation of classes with TC_H_ROOT\n\nThe function qdisc_tree_reduce_backlog() uses TC_H_ROOT as a termination\ncondition when traversing up the qdisc tree to update parent backlog\ncounters. However, if a class is created with classid TC_H_ROOT, the\ntraversal terminates prematurely at this class instead of reaching the\nactual root qdisc, causing parent statistics to be incorrectly maintained.\nIn case of DRR, this could lead to a crash as reported by Mingi Cho.\n\nPrevent the creation of any Qdisc class with classid TC_H_ROOT\n(0xFFFFFFFF) across all qdisc types, as suggested by Jamal.",
  "id": "GHSA-37v5-vmq6-f37g",
  "modified": "2025-11-03T21:33:26Z",
  "published": "2025-04-01T18:30:54Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-21971"
    },
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      "type": "WEB",
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      "url": "https://git.kernel.org/stable/c/0c3057a5a04d07120b3d0ec9c79568fceb9c921e"
    },
    {
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    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/78533c4a29ac3aeddce4b481770beaaa4f3bfb67"
    },
    {
      "type": "WEB",
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    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/94edfdfb9505ab608e86599d1d1e38c83816fc1c"
    },
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    },
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      "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"
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      "type": "CVSS_V3"
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}

CVE-2025-21971 (GCVE-0-2025-21971)

Vulnerability from cvelistv5 – Published: 2025-04-01 15:47 – Updated: 2026-08-05 11:55

Title

net_sched: Prevent creation of classes with TC_H_ROOT

Summary

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.

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

10 references

URL	Tags
https://git.kernel.org/stable/c/e05d9938b1b0ac40b…
https://git.kernel.org/stable/c/7a82fe67a9f4d7123…
https://git.kernel.org/stable/c/003d92c91cdb5a64b…
https://git.kernel.org/stable/c/e5ee00607bbfc97ef…
https://git.kernel.org/stable/c/78533c4a29ac3aedd…
https://git.kernel.org/stable/c/5c3ca9cb48b51bd72…
https://git.kernel.org/stable/c/94edfdfb9505ab608…
https://git.kernel.org/stable/c/0c3057a5a04d07120…
https://lists.debian.org/debian-lts-announce/2025…
https://lists.debian.org/debian-lts-announce/2025…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 066a3b5b2346febf9a655b444567b7138e3bb939 , < e05d9938b1b0ac40b6054cc5fa0ccbd9afd5ed4c (git) Affected: 066a3b5b2346febf9a655b444567b7138e3bb939 , < 7a82fe67a9f4d7123d8e5ba8f0f0806c28695006 (git) Affected: 066a3b5b2346febf9a655b444567b7138e3bb939 , < 003d92c91cdb5a64b25a9a74cb8543aac9a8bb48 (git) Affected: 066a3b5b2346febf9a655b444567b7138e3bb939 , < e5ee00607bbfc97ef1526ea95b6b2458ac9e7cb7 (git) Affected: 066a3b5b2346febf9a655b444567b7138e3bb939 , < 78533c4a29ac3aeddce4b481770beaaa4f3bfb67 (git) Affected: 066a3b5b2346febf9a655b444567b7138e3bb939 , < 5c3ca9cb48b51bd72bf76b8b05e24f3cd53db5e7 (git) Affected: 066a3b5b2346febf9a655b444567b7138e3bb939 , < 94edfdfb9505ab608e86599d1d1e38c83816fc1c (git) Affected: 066a3b5b2346febf9a655b444567b7138e3bb939 , < 0c3057a5a04d07120b3d0ec9c79568fceb9c921e (git)
Linux	Linux	Affected: 2.6.25 Unaffected: 0 , < 2.6.25 (semver) Unaffected: 5.4.292 , ≤ 5.4.* (semver) Unaffected: 5.10.236 , ≤ 5.10.* (semver) Unaffected: 5.15.180 , ≤ 5.15.* (semver) Unaffected: 6.1.132 , ≤ 6.1.* (semver) Unaffected: 6.6.84 , ≤ 6.6.* (semver) Unaffected: 6.12.20 , ≤ 6.12.* (semver) Unaffected: 6.13.8 , ≤ 6.13.* (semver) Unaffected: 6.14 , ≤ * (original_commit_for_fix)

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.