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CVE-2023-4207

HIGHCVSS 7.8/10EPSS 0.30%

Last modified

CVE-2023-4207 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. A use-after-free vulnerability in the Linux kernel's net/sched: cls_fw component can be exploited to achieve local privilege escalation. When fw_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free. We recommend upgrading past commit 76e42ae831991c828cffa8c37736ebfb831ad5ec.. EPSS estimates a 0.30% chance of exploitation in the next 30 days.

Description

A use-after-free vulnerability in the Linux kernel's net/sched: cls_fw component can be exploited to achieve local privilege escalation. When fw_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free. We recommend upgrading past commit 76e42ae831991c828cffa8c37736ebfb831ad5ec.

Metrics

CVSS 3.1
7.8/10

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

EPSS Probability
0.30%

21.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
LinuxLinux Kernel>= 3.18, < 4.14.326
LinuxLinux Kernel>= 4.15, < 4.19.295
LinuxLinux Kernel>= 4.20, < 5.4.253
LinuxLinux Kernel>= 5.5, < 5.10.190
LinuxLinux Kernel>= 5.11, < 5.15.126
LinuxLinux Kernel>= 5.16, < 6.1.45
LinuxLinux Kernel>= 6.2, < 6.4.10
DebianDebian Linux12.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2023-4207?
A use-after-free vulnerability in the Linux kernel's net/sched: cls_fw component can be exploited to achieve local privilege escalation. When fw_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free. We recommend upgrading past commit 76e42ae831991c828cffa8c37736ebfb831ad5ec.
How severe is CVE-2023-4207?
CVE-2023-4207 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.30% probability of exploitation in the next 30 days.
How do I fix CVE-2023-4207?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST