{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89746","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-11T19:38:34.762Z","datePublished":"2026-09-11T19:46:51.529Z","dateUpdated":"2026-09-14T12:02:27.816Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-14T12:02:27.816Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix use-after-free with same-name named triggers\n\nWhen two hist triggers on different events are registered with the same\nname=, the second one reuses the first as named_data.  Both are added to\ntr->hist_vars by save_hist_vars() during event_hist_trigger_parse(),\nbecause save_hist_vars() is called before event_trigger_register() while\nthe named reuse is only detected later, in hist_register_trigger().\n\nIn the named-data branch hist_register_trigger() then frees the second\nhistogram's hist_data via destroy_hist_data(), but never removes its\ntr->hist_vars list entry, leaving a dangling pointer and leaking the\ntrace_array reference it holds.\n\nA later hist trigger that references a variable makes find_var_file()\nwalk tr->hist_vars and dereference the freed hist_data.  The bug is\nreproducible from userspace by writing three hist triggers to tracefs:\n\n  cd /sys/kernel/tracing\n  echo 'hist:keys=common_pid:x=common_pid:name=mh' > events/sched/sched_switch/trigger\n  echo 'hist:keys=common_pid:x=common_pid:name=mh' > events/sched/sched_process_fork/trigger\n  echo 'hist:keys=common_pid:vals=$x' > events/sched/sched_process_exit/trigger\n\nThe third write panics the kernel:\n\n  BUG: KASAN: slab-use-after-free in find_var_file.part.0+0x272/0x290\n  Read of size 8 at addr ffff888001f8a0e0 by task sh/1\n  CPU: 1 UID: 0 PID: 1 Comm: sh Tainted: G      D          N\n  Call Trace:\n    find_var_file.part.0\n    find_event_var\n    parse_atom\n    parse_expr\n    __create_val_field\n    event_hist_trigger_parse\n    trigger_process_regex\n    event_trigger_write\n    vfs_write\n    ksys_write\n    do_syscall_64\n    entry_SYSCALL_64_after_hwframe\n  Allocated by task 1:\n    event_hist_trigger_parse\n  Freed by task 1:\n    hist_register_trigger+0x618/0xa30\n    event_hist_trigger_parse\n  The buggy address belongs to freed 2048-byte region\n  Oops: general protection fault ... RIP: find_var_file.part.0\n  Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b\n\nFix by removing the hist_data from tr->hist_vars and releasing the\ntrace_array reference in the named-data branch of hist_register_trigger()\nbefore freeing the hist_data."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The UAF is reached only by writing hist trigger commands to tracefs event trigger files via write(2) (event_trigger_write -> event_hist_trigger_parse). There is no network, adjacent-radio, or physical-device path into hist_register_trigger() or find_var_file().\nAC:L - Triggering is fully deterministic: two sequential same-name named hist writes free hist_data while leaving it on tr->hist_vars, and a third vals=$x write walks that dangling pointer. No race or victim state is required, and CONFIG_HIST_TRIGGERS is standard in distro and Android kernels.\nPR:L - The path has no capable() check; event_trigger_open() only enforces LOCKDOWN_TRACEFS and DAC (TRACE_MODE_WRITE 0640). Tracefs is routinely delegated to non-root tracing users (Android/Perfetto, ChromeOS debugd, gid= tracing mounts), matching prior named-hist UAF scores (CVE-2025-21899).\nUI:N - The attacker performs all three trigger writes themselves; no victim action, mount, or cooperating process is required.\nS:U - The slab use-after-free corrupts kernel heap objects in the tracing subsystem within the same OS security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - find_var_file() and find_var_field() dereference the freed 2048-byte hist_trigger_data (event_file, fields[]). After reclaiming that slab, the attacker controls those pointers, and create_var_ref() persists var_field->hist_data for later tracing_map reads, yielding an arbitrary kernel read primitive.\nI:H - The dangling hist_vars entry plus a sprayed hist_trigger_data lets create_var_ref() store attacker-controlled hist_data/map pointers into the new trigger; event_hist_trigger()/resolve_var_refs() then write tracing_map state through those pointers, a heap write primitive suitable for control-flow hijack.\nA:H - The commit reproduces a KASAN slab-use-after-free in find_var_file() that oopses or panics the kernel (including killing init). Any use-after-free of hist_data is a reliable whole-system crash even without successful exploitation."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/trace_events_hist.c"],"versions":[{"version":"5ae1b18f05ee2b849dc03b6c15d7da0c1c6efa77","lessThan":"441aa6742dff70297b5f64533a07a6189a026e91","status":"affected","versionType":"git"},{"version":"43b254d46c740bf9dbe65709afa021dd726dfa99","lessThan":"3a8534664426c071c2dfb5b4ffa36b18a2abfd79","status":"affected","versionType":"git"},{"version":"435d2964af815aae456db554c62963b4515f19d0","lessThan":"477d762be4b0ffaf01429ccd88859e93b0ec28cc","status":"affected","versionType":"git"},{"version":"6f86bdeab633a56d5c6dccf1a2c5989b6a5e323e","lessThan":"b1a49c22de01faf176d44e5caa765e237353a579","status":"affected","versionType":"git"},{"version":"6f86bdeab633a56d5c6dccf1a2c5989b6a5e323e","lessThan":"83d1ae0406d8eade219a81b401e201702dd9dc55","status":"affected","versionType":"git"},{"version":"6f86bdeab633a56d5c6dccf1a2c5989b6a5e323e","lessThan":"a7318172aa332a161fb9618286e64454c827f8fd","status":"affected","versionType":"git"},{"version":"f1ae50cfb818ce1ac7a674406dfadb7653e2552d","status":"affected","versionType":"git"},{"version":"6.1.130","lessThan":"6.1.188","status":"affected","versionType":"semver"},{"version":"6.6.81","lessThan":"6.6.157","status":"affected","versionType":"semver"},{"version":"6.12.18","lessThan":"6.12.109","status":"affected","versionType":"semver"},{"version":"6.13.6","lessThan":"6.14","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/trace_events_hist.c"],"versions":[{"version":"6.14","status":"affected"},{"version":"0","lessThan":"6.14","status":"unaffected","versionType":"semver"},{"version":"6.1.188","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.157","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.109","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.50","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.4","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc1","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":"6.1.130","versionEndExcluding":"6.1.188"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.81","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.18","versionEndExcluding":"6.12.109"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"6.18.50"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"7.2.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"7.3-rc1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13.6"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/441aa6742dff70297b5f64533a07a6189a026e91"},{"url":"https://git.kernel.org/stable/c/3a8534664426c071c2dfb5b4ffa36b18a2abfd79"},{"url":"https://git.kernel.org/stable/c/477d762be4b0ffaf01429ccd88859e93b0ec28cc"},{"url":"https://git.kernel.org/stable/c/b1a49c22de01faf176d44e5caa765e237353a579"},{"url":"https://git.kernel.org/stable/c/83d1ae0406d8eade219a81b401e201702dd9dc55"},{"url":"https://git.kernel.org/stable/c/a7318172aa332a161fb9618286e64454c827f8fd"}],"title":"tracing: Fix use-after-free with same-name named triggers","x_generator":{"engine":"bippy-1.2.0"}}}}