CVE-2025-21703

7.8 HIGH
Published: February 18, 2025 Modified: November 03, 2025

Description

In the Linux kernel, the following vulnerability has been resolved: netem: Update sch->q.qlen before qdisc_tree_reduce_backlog() qdisc_tree_reduce_backlog() notifies parent qdisc only if child qdisc becomes empty, therefore we need to reduce the backlog of the child qdisc before calling it. Otherwise it would miss the opportunity to call cops->qlen_notify(), in the case of DRR, it resulted in UAF since DRR uses ->qlen_notify() to maintain its active list.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://git.kernel.org/stable/c/1f8e3f4a4b8b90ad274dfbc66fc7d55cb582f4d5
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Patch
https://git.kernel.org/stable/c/6312555249082d6d8cc5321ff725df05482d8b83
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Patch
https://git.kernel.org/stable/c/638ba5089324796c2ee49af10427459c2de35f71
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Patch
https://git.kernel.org/stable/c/7b79ca9a1de6a428d486ff52fb3d602321c08f55
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Patch
https://git.kernel.org/stable/c/7f31d74fcc556a9166b1bb20515542de7bb939d1
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Patch
https://git.kernel.org/stable/c/839ecc583fa00fab785fde1c85a326743657fd32
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Patch
https://git.kernel.org/stable/c/98a2c685293aae122f688cde11d9334dddc5d207
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Patch
https://git.kernel.org/stable/c/e395fec75ac2dbffc99b4bce57b7f1f3c5449f2c
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Patch

9 reference(s) from NVD

Quick Stats

CVSS v3 Score
7.8 / 10.0
EPSS (Exploit Probability)
0.0%
4th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

linux