PT-2023-4896 · Linux+9 · Linux Kernel+9
Budimir Markovic
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Published
2023-08-25
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Updated
2025-03-20
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CVE-2023-4623
CVSS v3.1
7.8
High
| Vector | AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Name of the Vulnerable Software and Affected Versions
Linux kernel (affected versions not specified)
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.Recommendations
Upgrade past commit b3d26c5702c7d6c45456326e56d2ccf3f103e60f to resolve the issue. As a temporary workaround, consider restricting access to the vulnerable
sch hfsc component until a patch is available.Exploit
Fix
DoS
LPE
Use After Free
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Weakness Enumeration
Related Identifiers
Affected Products
Alt Linux
Almalinux
Astra Linux
Centos
Linuxmint
Linux Kernel
Red Hat
Red Os
Suse
Ubuntu