Vigie VulnDBEuropean-hosted Vulnerability DB
EN
Menu

net/sched: Enforce that teql can only be used as root qdisc (Linux Linux)

CVE-2026-23074
HIGH 7.8

En bref

Source
NVD
EPSS
EPSS 0.19 % · centile 9 ()
État
PUBLISHED
Publiée
Mise à jour
Attribuée par
Linux
Statut NVD
Modified

Rechercher sur…

Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: Enforce that teql can only be used as root qdisc Design intent of teql is that it is only supposed to be used as root qdisc. We need to check for that constraint. Although not important, I will describe the scenario that unearthed this issue for the curious. GangMin Kim <km.kim1503@gmail.com> managed to concot a scenario as follows: ROOT qdisc 1:0 (QFQ) ├── class 1:1 (weight=15, lmax=16384) netem with delay 6.4s └── class 1:2 (weight=1, lmax=1514) teql GangMin sends a packet which is enqueued to 1:1 (netem). Any invocation of dequeue by QFQ from this class will not return a packet until after 6.4s. In the meantime, a second packet is sent and it lands on 1:2. teql's enqueue will return success and this will activate class 1:2. Main issue is that teql only updates the parent visible qlen (sch->q.qlen) at dequeue. Since QFQ will only call dequeue if peek succeeds (and teql's peek always returns NULL), dequeue will never be called and thus the qlen will remain as 0. With that in mind, when GangMin updates 1:2's lmax value, the qfq_change_class calls qfq_deact_rm_from_agg. Since the child qdisc's qlen was not incremented, qfq fails to deactivate the class, but still frees its pointers from the aggregate. So when the first packet is rescheduled after 6.4 seconds (netem's delay), a dangling pointer is accessed causing GangMin's causing a UAF.

Faiblesses (CWE)

  • CWE-416 — Utilisation après libération
  • CWE-825 — Expired Pointer Dereference

Références

Scores

VersionScoreVecteurÉvalué par
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HLinux
CVSS 3.1HIGH 7.0CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:Hredhat-SADP
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · nvd@nist.gov (Primary)
CVSS 3.1HIGH 7.0CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary)

Références européennes

Avis du CERT-FR

Configurations affectées (CPE NVD)

Produits affectés

ProduitVersions
Linux · Linuxaffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 73d970ff0eddd874a84c953387c7f4464b705fc6 ; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ae810e6a8ac4fe25042e6825d2a401207a2e41fb ; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < dad49a67c2d817bfec98e6e45121b351e3a0202c ; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 0686bedfed34155520f3f735cbf3210cb9044380 ; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 4c7e8aa71c9232cba84c289b4b56cba80b280841 ; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 16ed73c1282d376b956bff23e5139add061767ba
Linux · Linuxaffected 2.6.12 ; unaffected 0 < 2.6.12 ; unaffected 5.10.249 ≤ 5.10.* ; unaffected 5.15.199 ≤ 5.15.* ; unaffected 6.1.162 ≤ 6.1.* ; unaffected 6.6.122 ≤ 6.6.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD