{"schema":"threatline.record/2","record":{"id":"CVE-2026-97918","aliases":[],"summary":"tracing: Undo the registration when enabling the histogram trigger fails","details":"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.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-97918","source_modified_at":"2026-10-21T12:53:37.796Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"067fe038e70f6e64960d26a79c4df5f1413d0f13","lessThan":"880712b6f48103ba3a04b154ff076d45fe86dcec","status":"affected","versionType":"git"},{"version":"067fe038e70f6e64960d26a79c4df5f1413d0f13","lessThan":"c7ee2d5733574d4694f7c0035e4381f54c1fca27","status":"affected","versionType":"git"},{"version":"067fe038e70f6e64960d26a79c4df5f1413d0f13","lessThan":"51b07104d563d4be2be34158d3b9d922ca417642","status":"affected","versionType":"git"},{"version":"067fe038e70f6e64960d26a79c4df5f1413d0f13","lessThan":"bfa6bc11aef93a3d9db0ac9564b734849a9d959b","status":"affected","versionType":"git"},{"version":"067fe038e70f6e64960d26a79c4df5f1413d0f13","lessThan":"92383cef66791a0c63a2f27755cadbdb2fbf270b","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-97918","source_modified_at":"2026-10-21T12:53:37.796Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"4.17","status":"affected"},{"version":"0","lessThan":"4.17","status":"unaffected","versionType":"semver"},{"version":"6.6.160","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.112","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.53","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.7","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-97918","source_modified_at":"2026-10-21T12:53:37.796Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"880712b6f48103ba3a04b154ff076d45fe86dcec","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-97918","source_modified_at":"2026-10-21T12:53:37.796Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"51b07104d563d4be2be34158d3b9d922ca417642","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-97918","source_modified_at":"2026-10-21T12:53:37.796Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"92383cef66791a0c63a2f27755cadbdb2fbf270b","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.002,"percentile":0.09328,"score_date":"2026-10-23"},"published_at":"2026-09-25T10:22:39.162Z","modified_at":"2026-10-21T12:53:37.796Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-97918","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-21T12:53:37.796Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-97918","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/880712b6f48103ba3a04b154ff076d45fe86dcec"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/c7ee2d5733574d4694f7c0035e4381f54c1fca27"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/51b07104d563d4be2be34158d3b9d922ca417642"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/bfa6bc11aef93a3d9db0ac9564b734849a9d959b"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/92383cef66791a0c63a2f27755cadbdb2fbf270b"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-21T12:53:37.796Z","content_hash":"5301a85af70d6c5a318dc21e721e93c69a75d53e660d98321d6afe038e7d818e"}}