{"api_version":"1","generated_at":"2026-08-23T18:12:08+00:00","cve":"CVE-2026-68283","urls":{"html":"https://cve.report/CVE-2026-68283","api":"https://cve.report/api/cve/CVE-2026-68283.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-68283","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-68283"},"summary":{"title":"tracing: Fix use-after-free freeing trigger private data","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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-10 13:20:17","updated_at":"2026-08-17 05:18:30"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","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","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","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","data":{"baseScore":8.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/79097812153b826fc156a2930ec8a90ed9edf4a2","name":"https://git.kernel.org/stable/c/79097812153b826fc156a2930ec8a90ed9edf4a2","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/b9c8a1400a3bf633f32820d184f3e05fed0f4af7","name":"https://git.kernel.org/stable/c/b9c8a1400a3bf633f32820d184f3e05fed0f4af7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-68283","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68283","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 61d445af0a7c70018111919e47beaaee15653f2f b9c8a1400a3bf633f32820d184f3e05fed0f4af7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 61d445af0a7c70018111919e47beaaee15653f2f 79097812153b826fc156a2930ec8a90ed9edf4a2 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.19","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.19 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.6 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"68283","cve":"CVE-2026-68283","epss":"0.003730000","percentile":"0.304640000","score_date":"2026-08-17","updated_at":"2026-08-18 00:11:47"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["kernel/trace/trace.h","kernel/trace/trace_events_hist.c","kernel/trace/trace_events_trigger.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"b9c8a1400a3bf633f32820d184f3e05fed0f4af7","status":"affected","version":"61d445af0a7c70018111919e47beaaee15653f2f","versionType":"git"},{"lessThan":"79097812153b826fc156a2930ec8a90ed9edf4a2","status":"affected","version":"61d445af0a7c70018111919e47beaaee15653f2f","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["kernel/trace/trace.h","kernel/trace/trace_events_hist.c","kernel/trace/trace_events_trigger.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.19"},{"lessThan":"6.19","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.6","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.6","versionStartIncluding":"6.19","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"6.19","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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."}],"metrics":[{"cvssV3_1":{"baseScore":8.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:N - Placeholder.\nAC:L - The attacker controls both sides of the race: one thread writes '!hist:'/'!enable_event:' to remove the trigger while another continuously fires the traced event, so an in-flight event_triggers_call() reader reliably touches hist_data/enable_data after they are freed inline.\nPR:L - Registering and removing triggers only needs write access to tracefs (TRACE_MODE_WRITE, DAC plus LOCKDOWN_TRACEFS, no capable() gate), which realistic deployments such as Android/perfetto, ChromeOS and gid=tracing mounts grant to unprivileged tracing users.\nUI:N - The attacker performs both the trigger removal and the event generation itself; no separate victim action is required.\nS:U - The use-after-free corrupts kernel heap memory within the same OS security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - A concurrent handler dereferences the freed hist_trigger_data (n_keys, fields[], key_size, tracing_map) and the freed enable_trigger_data->file, so reclaimed heap contents are read and can be reflected back through histogram output, giving arbitrary kernel memory disclosure.\nI:H - event_hist_trigger() writes into freed tracing_map elements and event_enable_trigger() writes event-file flags through a pointer read from freed enable_data, so heap spraying the reclaimed objects yields a controlled write primitive suitable for privilege escalation.\nA:H - Use-after-free of hist_data/cmd_ops/enable_data readily causes oops or panic in tracepoint context even without successful exploitation, and the race can be re-triggered at will."}]}],"providerMetadata":{"dateUpdated":"2026-08-17T05:02:18.147Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/b9c8a1400a3bf633f32820d184f3e05fed0f4af7"},{"url":"https://git.kernel.org/stable/c/79097812153b826fc156a2930ec8a90ed9edf4a2"}],"title":"tracing: Fix use-after-free freeing trigger private data","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-68283","datePublished":"2026-08-10T12:02:15.088Z","dateReserved":"2026-07-30T09:28:09.379Z","dateUpdated":"2026-08-17T05:02:18.147Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-10 13:20:17","lastModifiedDate":"2026-08-17 05:18:30","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":2.8,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"68283","Ordinal":"1","Title":"tracing: Fix use-after-free freeing trigger private data","CVE":"CVE-2026-68283","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"68283","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"tracing: Fix use-after-free freeing trigger private data"}]}}}