Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
AV AC PR UI S C I A CVSS EPSS %ile KEV L L L N U N N H 5.5 .0021 11.6 —
AFFECTED Product Versions Fixed Linux 066a3b5b2346febf9a655b444567b7138e3bb939 – — Linux 2.6.25 – 5.4.292
TIMELINE Dec 29 Reserved by Linux Apr 1 Published (CNA: Linux) Jul 30 RESCORED — CVE-2025-21971 (Linux). CVSS 7.8 → 5.5 (NVD).
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.
| Date | Event | Detail |
|---|---|---|
| December 29, 2024 | Reserved | Reserved by Linux |
| April 1, 2025 | Published | Published (CNA: Linux) |
| July 30, 2026 | RESCORED | RESCORED — CVE-2025-21971 (Linux). CVSS 7.8 → 5.5 (NVD). |
Authoritative record: CVE-2025-21971 at cve.org
Vendors: linux
Weaknesses: CWE-835
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2025-21971 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.