{"identifier":"CVE-2026-99234","cve":{"id":"CVE-2026-99234","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Unregister field variable histograms when the command fails\n\nAn action that names a field on another event needs that field as a\nvariable, so create_field_var_hist() registers a second hist trigger on\nthat event to provide it, and records it in\ntarget_hist_data->field_var_hists[].\n\nIf a later part of the same command fails, create_actions() returns an\nerror and event_hist_trigger_parse() jumps to out_free. The write fails\nwith -EINVAL and sched_switch gets no trigger, but:\n\n  # echo 'hist:keys=pid:ts0=common_timestamp.usecs' >> \\\n      events/sched/sched_waking/trigger\n  # echo 'my_synth u64 lat; int a; int b' >> synthetic_events\n  # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:\\\n      onmatch(sched.sched_waking).my_synth($wakeup_lat,prio,nosuchfld)'\\\n      >> events/sched/sched_switch/trigger\n  # cat events/sched/sched_waking/trigger\n  hist:keys=pid:vals=hitcount:ts0=common_timestamp.usecs:sort=hitcount:size=2048:clock=global [active]\n  hist:keys=pid:vals=hitcount:synthetic_prio=prio:sort=hitcount:size=2048 [active]\n\nThe second histogram is the one created for 'prio'. It is still active and\nstill counting.\n\nout_free reaches destroy_field_var_hists(), which frees the\nfield_var_hists[] entries, but never unregister_field_var_hists(), which is\nwhat removes the triggers and runs only from event_hist_trigger_free(). The\nentry is freed and the trigger is left with nothing tracking it.\n\nUnregister the field variable histograms in out_free as well, and record\neach one as soon as its trigger is registered rather than after the lookup\nthat follows it, so no exit can leave a registered trigger untracked. The\nentry then belongs to field_var_hists[] and is released by\ndestroy_field_var_hists(), so freeing it on that exit would be a double\nfree.","published":"2026-11-02T16:17:48.597000+00:00","modified":"2026-11-02T16:17:48.597000+00:00","status":"Received","score":null,"severity":"UNSCORED","vector":"","cvss_version":"","affected":[],"weaknesses":[],"references":[{"url":"https://git.kernel.org/stable/c/431959fc76456cbba539279fe8967aa9391e6f23","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5afb9317e2eeb1c7021a82995ce244fda5a4bd4f","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8482ec5b65f606d5bbcec518e0afc69ad65ca414","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a3d7ffd2409700748a495b645948fef48199206e","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/aae0ccd7326eef78dcdefffef3d1253e6f0615ca","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d0090baf02dd08f6e909f36f0ad54a4e80f5e79b","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/dba0f492703956801149cc70b39d2650a37995c3","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f21351d1c4cdcc6a68f03636a407c2af1a5e1e10","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"kev":null,"kev_checked":true,"metrics":{},"configurations":[],"source":"nvd","retrieved_at":"2026-11-02T19:29:45.319564+00:00","exploited":false,"kev_stale":false,"products":[],"priority":{"label":"Assess exposure and vendor guidance","reasons":["No higher-priority signal is available in the current stored evidence.","Fresh EPSS data is unavailable; missing values are not zero."]},"epss":null,"version_assessment":null},"news":[],"campaigns":[],"domains":[{"domain":"git.kernel.org","source_url":"https://git.kernel.org/stable/c/431959fc76456cbba539279fe8967aa9391e6f23","investigate_url":"https://investigate.aeglixmind.com/#git.kernel.org"}],"arsenal_url":"https://arsenal.aeglixmind.com/?cve=CVE-2026-99234","catalog_url":"https://cves.aeglixmind.com/cve/CVE-2026-99234","research_url":"https://investigate.aeglixmind.com/research/cve/CVE-2026-99234","coverage":{"news_candidates_checked":0,"campaign_candidates_checked":0,"bounded":false,"notice":"Exact CVE mentions in stored public excerpts and reviewed campaign content only. A mention is not proof of exploitation, attribution or tool suitability. Missing matches do not establish absence."}}