{"cve":"CVE-2026-97918","nvd":{"published":"2026-09-25T11:17:18.807","modified":"2026-10-21T13:21:16.053","status":"Received","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.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/51b07104d563d4be2be34158d3b9d922ca417642","https://git.kernel.org/stable/c/880712b6f48103ba3a04b154ff076d45fe86dcec","https://git.kernel.org/stable/c/92383cef66791a0c63a2f27755cadbdb2fbf270b","https://git.kernel.org/stable/c/bfa6bc11aef93a3d9db0ac9564b734849a9d959b","https://git.kernel.org/stable/c/c7ee2d5733574d4694f7c0035e4381f54c1fca27"],"products":[],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2026-97918","score":0.00206,"percentile":0.10564,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}