net_sched: Prevent creation of classes with TC_H_ROOT
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.
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
- Added to Heist Feed
- Publisher date