{"id":"CVE-2023-4921","revision":"6e3258e3108c494099351140da70cfca","records":[{"revision":"6e3258e3108c494099351140da70cfca","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2023-4921","aliases":[],"title":"Use-after-free in Linux kernel's net/sched: sch_qfq component","description":"A use-after-free vulnerability in the Linux kernel's net/sched: sch_qfq component can be exploited to achieve local privilege escalation.\n\nWhen the plug qdisc is used as a class of the qfq qdisc, sending network packets triggers use-after-free in qfq_dequeue() due to the incorrect .peek handler of sch_plug and lack of error checking in agg_dequeue().\n\nWe recommend upgrading past commit 8fc134fee27f2263988ae38920bc03da416b03d8.","state":0,"publishedAt":"2023-09-12T19:45:19.367+00:00","modifiedAt":"2026-10-14T21:49:38.794+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\": \"3.8\",\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=8fc134fee27f2263988ae38920bc03da416b03d8","https://kernel.dance/8fc134fee27f2263988ae38920bc03da416b03d8","https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html","https://lists.debian.org/debian-lts-announce/2024/01/msg00004.html"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2023-4921","license":"CVE Program Terms of Use","key":"cve-program:CVE-2023-4921","identifiers":["CVE-2023-4921"]},"retained":false,"historicalAffected":[]}],"coverage":[]}