{"id":"CVE-2026-89750","revision":"649cd3b127db4fc3b9525cf8cf649821","records":[{"revision":"649cd3b127db4fc3b9525cf8cf649821","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89750","aliases":[],"title":"tracing/user_events: Clear copied tracing state before fork duplication","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing/user_events: Clear copied tracing state before fork duplication\n\ndup_task_struct() copies user_event_mm from the parent into the child,\nwithout grabbing a reference to it. user_event_mm_dup() should\nreplace it, but it leaves that copied pointer unmodified if\nuser_event_mm_alloc() fails.\n\nWhen the child exits, user_event_mm_remove() decrements a reference\nthe child never owned, which ultimately frees user_event_mm, while\nthe parent still as a stale pointer to it. This creates a UAF, which\nKASAN reports as:\n\n    BUG: KASAN: slab-use-after-free in\n    current_user_event_mm+0x51/0x1d0 Write of size 4 at addr\n    ffff888005010d30 by task init/44\n\n    Call Trace:\n     <TASK>\n     kasan_report+0xce/0x100\n     kasan_check_range+0x10f/0x1e0\n     current_user_event_mm+0x51/0x1d0\n     user_events_ioctl+0x82e/0x15c0\n     __x64_sys_ioctl+0x139/0x1c0\n     do_syscall_64+0xce/0x450\n     entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\n    Allocated by task 44:\n     __kasan_kmalloc+0x8f/0xa0\n     __kmalloc_cache_noprof+0x180/0x3a0\n     user_event_mm_alloc+0x3c/0x1f0\n     current_user_event_mm+0x88/0x1d0\n\n    Freed by task 42:\n     __kasan_slab_free+0x43/0x70\n     kfree+0x13a/0x390\n     process_one_work+0x696/0xf90\n     worker_thread+0x420/0xba0\n\nThe fix simply clears the copied pointer before any possible failure.\nIn case of failure, the child then has nothing to free.","state":0,"publishedAt":"2026-09-11T19:46:54.565+00:00","modifiedAt":"2026-10-19T08:52:04.079+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"kernel/trace/trace_events_user.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"7235759084a4f8524a46bd2638885ff3b34ce279\",\n                            \"lessThan\": \"33ce55b368b64d65941867add00e7f288cbb8234\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7235759084a4f8524a46bd2638885ff3b34ce279\",\n                            \"lessThan\": \"63b39e49a4c9d68e010e96b26fc7374f0864f2b1\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7235759084a4f8524a46bd2638885ff3b34ce279\",\n                            \"lessThan\": \"25a0758cf6bdbfddac2be71124c9bd0692f4b0b1\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7235759084a4f8524a46bd2638885ff3b34ce279\",\n                            \"lessThan\": \"b799f67119aff179719a0b1e12441ebbdaaf62f9\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7235759084a4f8524a46bd2638885ff3b34ce279\",\n                            \"lessThan\": \"390f6bd8583d177029d9df4bea6667509e55a765\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"kernel/trace/trace_events_user.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.4\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.4\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.157\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.109\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.50\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.4\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\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/stable/c/33ce55b368b64d65941867add00e7f288cbb8234","https://git.kernel.org/stable/c/63b39e49a4c9d68e010e96b26fc7374f0864f2b1","https://git.kernel.org/stable/c/25a0758cf6bdbfddac2be71124c9bd0692f4b0b1","https://git.kernel.org/stable/c/b799f67119aff179719a0b1e12441ebbdaaf62f9","https://git.kernel.org/stable/c/390f6bd8583d177029d9df4bea6667509e55a765"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89750","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89750","identifiers":["CVE-2026-89750"]},"retained":false,"historicalAffected":[]}],"coverage":[]}