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net_sched: Prevent creation of classes with TC_H_ROOT

Type: advisorySource: Official CVE List1 source record

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.

Announced Source revision 1
Original source ↗

CVE-2025-21971

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2025-21971

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "066a3b5b2346febf9a655b444567b7138e3bb939",
        "lessThan": "e05d9938b1b0ac40b6054cc5fa0ccbd9afd5ed4c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "066a3b5b2346febf9a655b444567b7138e3bb939",
        "lessThan": "7a82fe67a9f4d7123d8e5ba8f0f0806c28695006",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "066a3b5b2346febf9a655b444567b7138e3bb939",
        "lessThan": "003d92c91cdb5a64b25a9a74cb8543aac9a8bb48",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "066a3b5b2346febf9a655b444567b7138e3bb939",
        "lessThan": "e5ee00607bbfc97ef1526ea95b6b2458ac9e7cb7",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "066a3b5b2346febf9a655b444567b7138e3bb939",
        "lessThan": "78533c4a29ac3aeddce4b481770beaaa4f3bfb67",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "066a3b5b2346febf9a655b444567b7138e3bb939",
        "lessThan": "5c3ca9cb48b51bd72bf76b8b05e24f3cd53db5e7",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "066a3b5b2346febf9a655b444567b7138e3bb939",
        "lessThan": "94edfdfb9505ab608e86599d1d1e38c83816fc1c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "066a3b5b2346febf9a655b444567b7138e3bb939",
        "lessThan": "0c3057a5a04d07120b3d0ec9c79568fceb9c921e",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/sched/sch_api.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "2.6.25"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "2.6.25",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.4.292",
        "versionType": "semver",
        "lessThanOrEqual": "5.4.*"
      },
      {
        "status": "unaffected",
        "version": "5.10.236",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.180",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.132",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.84",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.20",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.13.8",
        "versionType": "semver",
        "lessThanOrEqual": "6.13.*"
      },
      {
        "status": "unaffected",
        "version": "6.14",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/sched/sch_api.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2025-21971

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#30450 · Revision 1
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Publisher date
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