Use After Free in Linux Kernel
CVE-2023-4623
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.
Vulnerability class: Use-After-Free
EPSS: 0.003 (21.1th 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 2.6.12
- Linux Linux_kernel
- Debian Debian_linux — versions 10.0
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 (Mailing List, Third Party Advisory)
- cve-coordination@google.com (VDB Entry, Third Party Advisory)
- cve-coordination@google.com (Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2023-4623?
- CVE-2023-4623 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-2023-4623?
- High severity. CVSS v3 base score is 7.8 out of 10.
- Is CVE-2023-4623 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.