{"cve":"CVE-2026-68283","nvd":{"published":"2026-08-10T13:20:17.563","modified":"2026-08-17T05:18:30.910","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix use-after-free freeing trigger private data\n\nCommit 61d445af0a7c (\"tracing: Add bulk garbage collection of freeing\nevent_trigger_data\") moved the kfree() of event_trigger_data to a kthread\nthat runs tracepoint_synchronize_unregister() before freeing. That removed\nthe synchronization the trigger .free callbacks used to get implicitly and\ninline from trigger_data_free().\n\nevent_hist_trigger_free(), event_hist_trigger_named_free() and\nevent_enable_trigger_free() free their satellite data (hist_data, cmd_ops,\nenable_data) right after trigger_data_free() returns. With the\nsynchronization now deferred to the kthread, a concurrent tracepoint\nhandler can still reach that data through the list_del_rcu()'d trigger,\ncausing a use-after-free.\n\nThe histogram teardown must stay synchronous: remove_hist_vars() and\nunregister_field_var_hists() have to detach a synthetic event from the\nhistogram before the trigger-removal write returns, otherwise a following\ncommand races in and the synthetic-event removal fails with -EBUSY, as the\ntrigger-synthetic-eprobe.tc selftest catches. Make those callbacks wait\nwith the correct barrier - tracepoint_synchronize_unregister(), matching\nthe free kthread - before freeing.\n\nThe enable trigger has no such synchronous requirement, and a blocking\nsynchronize there would re-serialize the path that commit deliberately\ndeferred. Give it an optional private_data_free() callback that the free\nkthread runs after its grace period, and free enable_data from there.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":8.8},"cwes":[],"references":["https://git.kernel.org/stable/c/79097812153b826fc156a2930ec8a90ed9edf4a2","https://git.kernel.org/stable/c/b9c8a1400a3bf633f32820d184f3e05fed0f4af7"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:47:54.990491175+00:00"},"epss":{"cve":"CVE-2026-68283","score":0.00374,"percentile":0.31368,"date":"2026-10-31"},"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."]}