{"id":"CVE-2026-97918","revision":"caa6119b95ae46fcb700c971cdaaf1fe","records":[{"revision":"caa6119b95ae46fcb700c971cdaaf1fe","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-97918","aliases":[],"title":"tracing: Undo the registration when enabling the histogram trigger fails","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Undo the registration when enabling the histogram trigger fails\n\nCommit 6f86bdeab633 (\"tracing: Fix bad hist from corrupting named_triggers\nlist\") described how a trigger that is registered but not on file->triggers\nends up freed while still on the global named_triggers list, and moved the\nregistration down so that hist_trigger_enable() follows it immediately. One\npath still gets there. hist_trigger_enable() adds the trigger and takes it\nstraight back out when the event cannot be enabled:\n\n\tlist_add_tail_rcu(&data->list, &file->triggers);\n\n\tupdate_cond_flag(file);\n\n\tif (trace_event_trigger_enable_disable(file, 1) < 0) {\n\t\tlist_del_rcu(&data->list);\n\t\tupdate_cond_flag(file);\n\t\tret--;\n\t}\n\nso the list walk in hist_unregister_trigger() matches nothing, test stays\nNULL, and the ->free() that would call del_named_trigger() is skipped.\nout_unreg falls through to out_free, which frees the trigger anyway:\n\n BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0\n Read of size 8 at addr ffff8880091d3160 by task init/1\n find_named_trigger+0xac/0xc0\n hist_register_trigger+0xc1/0xa00\n event_hist_trigger_parse+0x3146/0x6af0\n event_trigger_write+0xce/0x160\n Freed by task 69:\n kfree+0x154/0x420\n trigger_kthread_fn+0xfd/0x160\n\nLeave the trigger where hist_unregister_trigger() can find it and let that\nundo the registration, which is the only code that knows all of what\ncmd_ops->init() took: the named list entry, the hist_pad reference, the\nreference on the trigger a named histogram is shared with, and the copied\ncmd_ops. It also pairs the failed trace_event_trigger_enable_disable(),\nwhose sm_ref and buffered event reference are otherwise left behind.\n\nSince ->free() releases trigger_data and, for a trigger that does not share\nits histogram, hist_data with it, out_unreg can no longer fall through to\nout_free. For a trigger that does share, hist_register_trigger() has\nalready destroyed the caller's hist_data, so the fall-through was reading\nfreed memory there as well.\n\nMove the enable_timestamps check in hist_unregister_trigger() above the\n->free() call for the same reason: hist_data does not outlive it once the\ntrigger being removed is the one that owns it.","state":0,"publishedAt":"2026-09-25T10:22:39.162+00:00","modifiedAt":"2026-10-21T12:53:37.796+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_hist.c\"\n ],\n \"versions\": [\n {\n \"version\": \"067fe038e70f6e64960d26a79c4df5f1413d0f13\",\n \"lessThan\": \"880712b6f48103ba3a04b154ff076d45fe86dcec\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"067fe038e70f6e64960d26a79c4df5f1413d0f13\",\n \"lessThan\": \"c7ee2d5733574d4694f7c0035e4381f54c1fca27\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"067fe038e70f6e64960d26a79c4df5f1413d0f13\",\n \"lessThan\": \"51b07104d563d4be2be34158d3b9d922ca417642\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"067fe038e70f6e64960d26a79c4df5f1413d0f13\",\n \"lessThan\": \"bfa6bc11aef93a3d9db0ac9564b734849a9d959b\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"067fe038e70f6e64960d26a79c4df5f1413d0f13\",\n \"lessThan\": \"92383cef66791a0c63a2f27755cadbdb2fbf270b\",\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_hist.c\"\n ],\n \"versions\": [\n {\n \"version\": \"4.17\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"4.17\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.160\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.112\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.53\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.2.7\",\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":[],"references":["https://git.kernel.org/stable/c/880712b6f48103ba3a04b154ff076d45fe86dcec","https://git.kernel.org/stable/c/c7ee2d5733574d4694f7c0035e4381f54c1fca27","https://git.kernel.org/stable/c/51b07104d563d4be2be34158d3b9d922ca417642","https://git.kernel.org/stable/c/bfa6bc11aef93a3d9db0ac9564b734849a9d959b","https://git.kernel.org/stable/c/92383cef66791a0c63a2f27755cadbdb2fbf270b"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-97918","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-97918","identifiers":["CVE-2026-97918"]},"retained":false,"historicalAffected":[]}],"coverage":[]}