CVE-2023-4623 Use-after-free in Linux kernel's net/sched: sch_hfsc (HFSC qdisc traffic control) component

2023-09-0613:56:57

CWE-416

Google

www.cve.org

vulnerability

linux kernel

net/sched

use-after-free

hfsc qdisc traffic control

local privilege escalation

link-sharing curve

parent

commit

b3d26c5702c7d6c45456326e56d2ccf3f103e60f

7.8 High

CVSS3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

7.8 High

AI Score

Confidence

High

0.0004 Low

EPSS

Percentile

5.1%

JSON

A use-after-free vulnerability in the Linux kernel’s net/sched: sch_hfsc (HFSC qdisc traffic control) component can be exploited to achieve local privilege escalation.

If a class with a link-sharing curve (i.e. with the HFSC_FSC flag set) has a parent without a link-sharing curve, then init_vf() will call vttree_insert() on the parent, but vttree_remove() will be skipped in update_vf(). This leaves a dangling pointer that can cause a use-after-free.

We recommend upgrading past commit b3d26c5702c7d6c45456326e56d2ccf3f103e60f.

CNA Affected

[
  {
    "vendor": "Linux",
    "product": "Kernel",
    "packageName": "kernel",
    "repo": "https://git.kernel.org",
    "versions": [
      {
        "status": "affected",
        "version": "2.6.12",
        "lessThan": "6.6",
        "versionType": "custom"
      }
    ],
    "defaultStatus": "unaffected"
  }
]