{"id":"CVE-2023-4921","details":"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.","modified":"2026-03-13T07:46:44.607056Z","published":"2023-09-12T20:15:10.573Z","related":["ALSA-2024:0897","MGASA-2023-0295","MGASA-2023-0296","SUSE-SU-2023:4030-1","SUSE-SU-2023:4031-1","SUSE-SU-2023:4032-1","SUSE-SU-2023:4033-1","SUSE-SU-2023:4035-1","SUSE-SU-2023:4057-1","SUSE-SU-2023:4058-1","SUSE-SU-2023:4071-1","SUSE-SU-2023:4072-1","SUSE-SU-2023:4072-2","SUSE-SU-2023:4093-1","SUSE-SU-2023:4095-1","SUSE-SU-2023:4142-1","SUSE-SU-2023:4347-1","SUSE-SU-2024:0469-1","SUSE-SU-2024:0474-1","SUSE-SU-2024:0478-1","SUSE-SU-2024:0514-1","SUSE-SU-2024:0515-1","SUSE-SU-2024:0516-1","SUSE-SU-2024:0622-1","SUSE-SU-2024:0624-1","SUSE-SU-2024:0655-1","SUSE-SU-2024:0666-1","SUSE-SU-2024:0685-1","SUSE-SU-2024:0698-1","SUSE-SU-2024:0727-1","USN-6454-1","USN-6454-2","USN-6454-3","USN-6454-4"],"references":[{"type":"ADVISORY","url":"https://lists.debian.org/debian-lts-announce/2024/01/msg00004.html"},{"type":"ADVISORY","url":"https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html"},{"type":"FIX","url":"https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8fc134fee27f2263988ae38920bc03da416b03d8"},{"type":"FIX","url":"https://kernel.dance/8fc134fee27f2263988ae38920bc03da416b03d8"}],"affected":[{"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2023-4921.json","unresolved_ranges":[{"events":[{"introduced":"3.8"},{"fixed":"4.14.326"}]},{"events":[{"introduced":"4.15"},{"fixed":"4.19.295"}]},{"events":[{"introduced":"4.20"},{"fixed":"5.4.257"}]},{"events":[{"introduced":"5.5"},{"fixed":"5.10.195"}]},{"events":[{"introduced":"5.11"},{"fixed":"5.15.132"}]},{"events":[{"introduced":"5.16"},{"fixed":"6.1.54"}]},{"events":[{"introduced":"6.2"},{"fixed":"6.5.4"}]},{"events":[{"introduced":"0"},{"last_affected":"10.0"}]}]}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}