Use After Free in Linux Kernel
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.
Vulnerability class: Use-After-Free
EPSS: 0.003 (22.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Linux Kernel — versions 3.18
- Linux Linux_kernel
- Debian Debian_linux — versions 12.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- cve-coordination@google.com (Patch, Mailing List, patch, Issue Tracking, Vendor Advisory)
- cve-coordination@google.com (Patch, Vendor Advisory)
- cve-coordination@google.com (Third Party Advisory)
- cve-coordination@google.com (Mailing List, VDB Entry, Third Party Advisory)
Frequently asked questions
- What is CVE-2023-4207?
- CVE-2023-4207 is a high-severity vulnerability in Linux Kernel, classified under Use After Free. CVSS score: 7.8/10. Published 2023-09-06.
- How severe is CVE-2023-4207?
- High severity. CVSS v3 base score is 7.8 out of 10.
- Is CVE-2023-4207 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.