{"id":"CVE-2026-89746","title":"tracing: Fix use-after-free with same-name named triggers","summary":"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 firs…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","cwe":["CWE-825"],"vendor":"Linux","product":"Linux","affected":["Linux >= 5ae1b18f05ee2b849dc03b6c15d7da0c1c6efa77 < 441aa6742dff70297b5f64533a07a6189a026e91","Linux >= 43b254d46c740bf9dbe65709afa021dd726dfa99 < 3a8534664426c071c2dfb5b4ffa36b18a2abfd79","Linux >= 435d2964af815aae456db554c62963b4515f19d0 < 477d762be4b0ffaf01429ccd88859e93b0ec28cc","Linux >= 6f86bdeab633a56d5c6dccf1a2c5989b6a5e323e < b1a49c22de01faf176d44e5caa765e237353a579","Linux >= 6f86bdeab633a56d5c6dccf1a2c5989b6a5e323e < 83d1ae0406d8eade219a81b401e201702dd9dc55","Linux >= 6f86bdeab633a56d5c6dccf1a2c5989b6a5e323e < a7318172aa332a161fb9618286e64454c827f8fd","Linux f1ae50cfb818ce1ac7a674406dfadb7653e2552d","Linux >= 6.1.130 < 6.1.188","Linux >= 6.6.81 < 6.6.157","Linux >= 6.12.18 < 6.12.109","Linux >= 6.13.6 < 6.14","Linux 6.14"],"published":"2026-09-11","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:52:00.175Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89746","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"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89746.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89746"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532209"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89746"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89746"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89746.mbox"}],"tags":["cve.org","csaf","vex","red-hat"],"epss":0.00164,"epssPercentile":0.05553,"scores":{"cna":7.8,"vendor":7},"ingestedAt":"2026-09-14T15:23:07.449Z","slug":"CVE-2026-89746","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= 5ae1b18f05ee2b849dc03b6c15d7da0c1c6efa77 < 441aa6742dff70297b5f64533a07a6189a026e91`\n- `Linux >= 43b254d46c740bf9dbe65709afa021dd726dfa99 < 3a8534664426c071c2dfb5b4ffa36b18a2abfd79`\n- `Linux >= 435d2964af815aae456db554c62963b4515f19d0 < 477d762be4b0ffaf01429ccd88859e93b0ec28cc`\n- `Linux >= 6f86bdeab633a56d5c6dccf1a2c5989b6a5e323e < b1a49c22de01faf176d44e5caa765e237353a579`\n- `Linux >= 6f86bdeab633a56d5c6dccf1a2c5989b6a5e323e < 83d1ae0406d8eade219a81b401e201702dd9dc55`\n- `Linux >= 6f86bdeab633a56d5c6dccf1a2c5989b6a5e323e < a7318172aa332a161fb9618286e64454c827f8fd`\n- `Linux f1ae50cfb818ce1ac7a674406dfadb7653e2552d`\n- `Linux >= 6.1.130 < 6.1.188`\n- `Linux >= 6.6.81 < 6.6.157`\n- `Linux >= 6.12.18 < 6.12.109`\n- `Linux >= 6.13.6 < 6.14`\n- `Linux 6.14`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89746.json)","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":224577,"id":"CVE-2026-89746","ts":1792401417893,"field":"cvss","old":"7","new":"7.8"},{"seq":208948,"id":"CVE-2026-89746","ts":1790062298019,"field":"cvss","old":"7.8","new":"7"},{"seq":183853,"id":"CVE-2026-89746","ts":1789356677686,"field":"cvss","old":"7.8","new":"4.4"},{"seq":183852,"id":"CVE-2026-89746","ts":1789356677686,"field":"severity","old":"high","new":"medium"},{"seq":153632,"id":"CVE-2026-89746","ts":1789285351635,"field":"cvss","old":null,"new":"7.8"},{"seq":153631,"id":"CVE-2026-89746","ts":1789285351635,"field":"severity","old":"none","new":"high"},{"seq":147544,"id":"CVE-2026-89746","ts":1789270211324,"field":"cvss","old":null,"new":"4.4"},{"seq":147543,"id":"CVE-2026-89746","ts":1789270211324,"field":"severity","old":"none","new":"medium"},{"seq":109296,"id":"CVE-2026-89746","ts":1789183731322,"field":"cvss","old":null,"new":"4.4"},{"seq":109295,"id":"CVE-2026-89746","ts":1789183731322,"field":"severity","old":"none","new":"medium"}]}