{"cve":"CVE-2023-52707","nvd":{"published":"2024-05-21T16:15:12.993","modified":"2026-08-04T10:18:38.603","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched/psi: Fix use-after-free in ep_remove_wait_queue()\n\nIf a non-root cgroup gets removed when there is a thread that registered\ntrigger and is polling on a pressure file within the cgroup, the polling\nwaitqueue gets freed in the following path:\n\n do_rmdir\n   cgroup_rmdir\n     kernfs_drain_open_files\n       cgroup_file_release\n         cgroup_pressure_release\n           psi_trigger_destroy\n\nHowever, the polling thread still has a reference to the pressure file and\nwill access the freed waitqueue when the file is closed or upon exit:\n\n fput\n   ep_eventpoll_release\n     ep_free\n       ep_remove_wait_queue\n         remove_wait_queue\n\nThis results in use-after-free as pasted below.\n\nThe fundamental problem here is that cgroup_file_release() (and\nconsequently waitqueue's lifetime) is not tied to the file's real lifetime.\nUsing wake_up_pollfree() here might be less than ideal, but it is in line\nwith the comment at commit 42288cb44c4b (\"wait: add wake_up_pollfree()\")\nsince the waitqueue's lifetime is not tied to file's one and can be\nconsidered as another special case. While this would be fixable by somehow\nmaking cgroup_file_release() be tied to the fput(), it would require\nsizable refactoring at cgroups or higher layer which might be more\njustifiable if we identify more cases like this.\n\n  BUG: KASAN: use-after-free in _raw_spin_lock_irqsave+0x60/0xc0\n  Write of size 4 at addr ffff88810e625328 by task a.out/4404\n\n\tCPU: 19 PID: 4404 Comm: a.out Not tainted 6.2.0-rc6 #38\n\tHardware name: Amazon EC2 c5a.8xlarge/, BIOS 1.0 10/16/2017\n\tCall Trace:\n\t<TASK>\n\tdump_stack_lvl+0x73/0xa0\n\tprint_report+0x16c/0x4e0\n\tkasan_report+0xc3/0xf0\n\tkasan_check_range+0x2d2/0x310\n\t_raw_spin_lock_irqsave+0x60/0xc0\n\tremove_wait_queue+0x1a/0xa0\n\tep_free+0x12c/0x170\n\tep_eventpoll_release+0x26/0x30\n\t__fput+0x202/0x400\n\ttask_work_run+0x11d/0x170\n\tdo_exit+0x495/0x1130\n\tdo_group_exit+0x100/0x100\n\tget_signal+0xd67/0xde0\n\tarch_do_signal_or_restart+0x2a/0x2b0\n\texit_to_user_mode_prepare+0x94/0x100\n\tsyscall_exit_to_user_mode+0x20/0x40\n\tdo_syscall_64+0x52/0x90\n\tentry_SYSCALL_64_after_hwframe+0x63/0xcd\n\t</TASK>\n\n Allocated by task 4404:\n\n\tkasan_set_track+0x3d/0x60\n\t__kasan_kmalloc+0x85/0x90\n\tpsi_trigger_create+0x113/0x3e0\n\tpressure_write+0x146/0x2e0\n\tcgroup_file_write+0x11c/0x250\n\tkernfs_fop_write_iter+0x186/0x220\n\tvfs_write+0x3d8/0x5c0\n\tksys_write+0x90/0x110\n\tdo_syscall_64+0x43/0x90\n\tentry_SYSCALL_64_after_hwframe+0x63/0xcd\n\n Freed by task 4407:\n\n\tkasan_set_track+0x3d/0x60\n\tkasan_save_free_info+0x27/0x40\n\t____kasan_slab_free+0x11d/0x170\n\tslab_free_freelist_hook+0x87/0x150\n\t__kmem_cache_free+0xcb/0x180\n\tpsi_trigger_destroy+0x2e8/0x310\n\tcgroup_file_release+0x4f/0xb0\n\tkernfs_drain_open_files+0x165/0x1f0\n\tkernfs_drain+0x162/0x1a0\n\t__kernfs_remove+0x1fb/0x310\n\tkernfs_remove_by_name_ns+0x95/0xe0\n\tcgroup_addrm_files+0x67f/0x700\n\tcgroup_destroy_locked+0x283/0x3c0\n\tcgroup_rmdir+0x29/0x100\n\tkernfs_iop_rmdir+0xd1/0x140\n\tvfs_rmdir+0xfe/0x240\n\tdo_rmdir+0x13d/0x280\n\t__x64_sys_rmdir+0x2c/0x30\n\tdo_syscall_64+0x43/0x90\n\tentry_SYSCALL_64_after_hwframe+0x63/0xcd","cvss_v4":null,"cvss_v3":{"version":"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},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/7caeb5457bd01ccba0df1d6f4872f20d28e50b38","https://git.kernel.org/stable/c/c2dbe32d5db5c4ead121cf86dabd5ab691fb47fe","https://git.kernel.org/stable/c/c6879a4dcefe92d870ab68cabaa9caeda4f2af5a","https://git.kernel.org/stable/c/cca2b3feb70170ef6f0fbc4b4d91eea235a2b73a","https://git.kernel.org/stable/c/ec9c7aa08819f976b2492fa63c41b5712d2924b5"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:50:30.954589733+00:00"},"epss":{"cve":"CVE-2023-52707","score":0.00264,"percentile":0.18391,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}