CVE-2023-4623

Advisory lineage Upstream: 0 Downstream: 96
Analyzed
Published: 06 Sept 2023, 13:56
Last modified:27 Feb 2025, 21:00

Vulnerability Summary

Overall Risk (default)
medium
31/100
CVSS Score
7.8 HIGH
v3.1 (cve.org)
EPSS Score
0.02% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

06 Sept 2023, 13:56
Published
Vulnerability first disclosed
27 Feb 2025, 21:00
Last Modified
Vulnerability information updated

Description

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.

CVSS Metrics

  • v3.1•HIGH•Score: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Trends

Current EPSS score: 0.02%• Percentile: 5%

Techniques & Countermeasures

  • CWE-416•Use After Free

    The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Affected Systems

  • debian•debian_linux

    10.0

  • Unknown•Kernel

    ≥ 2.6.12, < 6.6

  • linux•linux_kernel

    ≥ 2.6.12, < 4.14.327 | ≥ 4.15, < 4.19.295 | ≥ 4.20, < 5.4.257 | ≥ 5.5, < 5.10.195 | ≥ 5.11, < 5.15.132 | ≥ 5.16, < 6.1.53 | ≥ 6.2, < 6.4.16 | ≥ 6.5, < 6.5.3

References (5)