{"id":"CVE-2023-4623","revision":"7a6d4ec23fc24e7086b37f0df7eceaad","records":[{"revision":"7a6d4ec23fc24e7086b37f0df7eceaad","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2023-4623","aliases":[],"title":"Use-after-free in Linux kernel's net/sched: sch_hfsc (HFSC qdisc traffic control) component","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.\n\nIf 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.\n\nWe recommend upgrading past commit b3d26c5702c7d6c45456326e56d2ccf3f103e60f.","state":0,"publishedAt":"2023-09-06T13:56:57.295+00:00","modifiedAt":"2026-10-14T21:36:21.987+00:00","affected":[{"ecosystem":"Vendor product","name":"kernel","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Linux\",\n                    \"product\": \"Kernel\",\n                    \"packageName\": \"kernel\",\n                    \"repo\": \"https://git.kernel.org\",\n                    \"versions\": [\n                        {\n                            \"status\": \"affected\",\n                            \"version\": \"2.6.12\",\n                            \"lessThan\": \"6.6\",\n                            \"versionType\": \"custom\"\n                        }\n                    ],\n                    \"defaultStatus\": \"unaffected\"\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b3d26c5702c7d6c45456326e56d2ccf3f103e60f","https://kernel.dance/b3d26c5702c7d6c45456326e56d2ccf3f103e60f","https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html","http://packetstormsecurity.com/files/175963/Kernel-Live-Patch-Security-Notice-LSN-0099-1.html","https://lists.debian.org/debian-lts-announce/2024/01/msg00004.html"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2023-4623","license":"CVE Program Terms of Use","key":"cve-program:CVE-2023-4623","identifiers":["CVE-2023-4623"]},"retained":false,"historicalAffected":[]}],"coverage":[]}