{"id":"CVE-2026-68283","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-68283","summary":"tracing: Fix use-after-free freeing trigger private data","details":"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.","published":"2026-08-10T12:02:15.088Z","modified":"2026-08-14T04:04:00.410792863Z","cvss":{"score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"7.1.6"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/79097812153b826fc156a2930ec8a90ed9edf4a2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b9c8a1400a3bf633f32820d184f3e05fed0f4af7"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68283.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68283"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-14T04:04:00.410792863Z"}}