CVE-2023-4921— Use-after-free in Linux kernel's net/sched: sch_qfq component
Quick assessment
Affected
Linux Kernel
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在资源管理错误漏洞，该漏洞源于存在释放后重用漏洞，可以实现本地权限提升。
Possible ATT&CK Techniques 2 AI
T1068 · Exploitation for Privilege Escalation T1203 · Exploitation for Client Execution
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I. Basic Information for CVE-2023-4921
Vulnerability Information
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Vulnerability Title
Use-after-free in Linux kernel's net/sched: sch_qfq component
Source: CVE Program / CVE List V5
Vulnerability Description
A use-after-free vulnerability in the Linux kernel's net/sched: sch_qfq component can be exploited to achieve local privilege escalation.
When the plug qdisc is used as a class of the qfq qdisc, sending network packets triggers use-after-free in qfq_dequeue() due to the incorrect .peek handler of sch_plug and lack of error checking in agg_dequeue().
We recommend upgrading past commit 8fc134fee27f2263988ae38920bc03da416b03d8.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
释放后使用
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在资源管理错误漏洞，该漏洞源于存在释放后重用漏洞，可以实现本地权限提升。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2023-4921
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Patches & Fixes for CVE-2023-4921 (1)
Mailing List Discussions for CVE-2023-4921 (2)
Other References for CVE-2023-4921 (1)
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V. Comments for CVE-2023-4921
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