{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2023-54019", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-12-24T10:53:46.179Z", "datePublished": "2025-12-24T10:55:49.840Z", "dateUpdated": "2026-08-05T09:16:37.375Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T09:16:37.375Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched/psi: use kernfs polling functions for PSI trigger polling\n\nDestroying psi trigger in cgroup_file_release causes UAF issues when\na cgroup is removed from under a polling process. This is happening\nbecause cgroup removal causes a call to cgroup_file_release while the\nactual file is still alive. Destroying the trigger at this point would\nalso destroy its waitqueue head and if there is still a polling process\non that file accessing the waitqueue, it will step on the freed pointer:\n\ndo_select\n vfs_poll\n do_rmdir\n cgroup_rmdir\n kernfs_drain_open_files\n cgroup_file_release\n cgroup_pressure_release\n psi_trigger_destroy\n wake_up_pollfree(&t->event_wait)\n// vfs_poll is unblocked\n synchronize_rcu\n kfree(t)\n poll_freewait -> UAF access to the trigger's waitqueue head\n\nPatch [1] fixed this issue for epoll() case using wake_up_pollfree(),\nhowever the same issue exists for synchronous poll() case.\nThe root cause of this issue is that the lifecycles of the psi trigger's\nwaitqueue and of the file associated with the trigger are different. Fix\nthis by using kernfs_generic_poll function when polling on cgroup-specific\npsi triggers. It internally uses kernfs_open_node->poll waitqueue head\nwith its lifecycle tied to the file's lifecycle. This also renders the\nfix in [1] obsolete, so revert it.\n\n[1] commit c2dbe32d5db5 (\"sched/psi: Fix use-after-free in ep_remove_wait_queue()\")" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerability is reached entirely through local syscalls (open/write/poll on a cgroup pressure file plus rmdir of the cgroup); there is no network component.\nAC:L - The attacker controls both racing sides (the polling thread and the rmdir that triggers psi_trigger_destroy) and can loop the sequence and tune scheduling to reliably win the race after kfree.\nPR:L - In the affected 6.4.y/6.5-rc code, psi_trigger_create explicitly allows unprivileged users to create 2s-window pollable triggers with no CAP_SYS_RESOURCE gate, reachable via systemd-delegated cgroups or user namespaces by an ordinary local user.\nUI:N - The attacker performs the poll and the cgroup removal itself; no action from any other user is required.\nS:U - The use-after-free is confined to the kernel's own memory and security authority, with no crossing of a VM/IOMMU/sandbox boundary.\nC:H - A use-after-free on the freed psi_trigger slab lets the attacker reallocate it with controlled contents and read back through the waitqueue pointer dereferences, enabling kernel memory disclosure.\nI:H - poll_freewait's remove_wait_queue performs list_del writes into the freed (and reallocatable) object, giving a write primitive that can be leveraged for arbitrary write / control-flow hijack via heap spraying.\nA:H - The use-after-free corrupts kernel heap state and reliably causes an oops/panic, resulting in denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/psi.h", "include/linux/psi_types.h", "kernel/cgroup/cgroup.c", "kernel/sched/psi.c" ], "versions": [ { "version": "0e94682b73bfa6c44c98af7a26771c9c08c055d5", "lessThan": "92cc0153324b6ae8577a39f5bf2cd83c9a34ea6a", "status": "affected", "versionType": "git" }, { "version": "0e94682b73bfa6c44c98af7a26771c9c08c055d5", "lessThan": "d124ab17024cc85a1079b7810a018a497ebc13da", "status": "affected", "versionType": "git" }, { "version": "0e94682b73bfa6c44c98af7a26771c9c08c055d5", "lessThan": "aff037078ecaecf34a7c2afab1341815f90fba5e", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/psi.h", "include/linux/psi_types.h", "kernel/cgroup/cgroup.c", "kernel/sched/psi.c" ], "versions": [ { "version": "5.2", "status": "affected" }, { "version": "0", "lessThan": "5.2", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.42", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.4.7", "lessThanOrEqual": "6.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.5", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.2", "versionEndExcluding": "6.1.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.2", "versionEndExcluding": "6.4.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.2", "versionEndExcluding": "6.5" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/92cc0153324b6ae8577a39f5bf2cd83c9a34ea6a" }, { "url": "https://git.kernel.org/stable/c/d124ab17024cc85a1079b7810a018a497ebc13da" }, { "url": "https://git.kernel.org/stable/c/aff037078ecaecf34a7c2afab1341815f90fba5e" } ], "title": "sched/psi: use kernfs polling functions for PSI trigger polling", "x_generator": { "engine": "bippy-1.2.0" } } } }