{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-99233", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.402Z", "datePublished": "2026-11-02T16:06:40.643Z", "dateUpdated": "2026-11-02T16:06:40.643Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-11-02T16:06:40.643Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing/histograms: Verify event_call identity when updating synth_event refcount\n\nIn event_hist_trigger_parse() and hist_unreg_all(), the histogram\nregistration and unregistration paths look up find_synth_event() using\ntrace_event_name(file->event_call) and adjust se->ref if a match is\nfound.\n\nBecause find_synth_event() only compares the event basename, registering\nor removing a histogram on a non-synthetic trace event whose basename\nmatches a synthetic event erroneously modifies the synthetic event's\nreference count. If a histogram is registered on the non-synthetic\nevent before the synthetic event is created and removed afterwards,\nse->ref is decremented without a matching increment, allowing the\nsynthetic event to be freed while an active histogram action still holds\na pointer to it.\n\nIntroduce find_synth_event_call() to verify that &se->call matches\nfile->event_call before adjusting se->ref."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - The colliding basename is supplied by local writes: event_trigger_write() \u2192 trigger_process_regex() \u2192 event_hist_trigger_parse()/hist_unreg_all() on events/<system>/<event>/trigger, and synth_events_write() \u2192 create_or_delete_synth_event() on synthetic_events. No network protocol carries this input.\nAC:L - The attacker drives a fully ordered sequence: a hist on a non-synth event (no se->ref++), then a same-basename synth event, then an ACTION_TRACE hist that stores data->synth_event and increments se->ref, then the !hist/hist_unreg_all path which decrements se->ref, then synth_event_delete(). event_mutex serializes it; no victim-owned state is required.\nPR:L - event_trigger_open() and synth_events_open() only call security_locked_down(LOCKDOWN_TRACEFS); both files are TRACE_MODE_WRITE (0640) with no capable() check. tracefs_parse_param() accepts uid=/gid= and tracefs_apply_options() applies that owner, so a delegated tracing user can write them; tracefs has no FS_USERNS_MOUNT.\nUI:N - The attacker writes the hist commands, creates and deletes the colliding synth event via synth_events_write(), and can fire the leftover ACTION_TRACE histogram from their own process (any syscall that hits the remaining event). No separate victim action is required.\nS:U - destroy_synth_event() kfree's struct synth_event while action_trace() still holds data->synth_event; that UAF is confined to the host tracing heap and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - Once free_synth_event() has kfree'd the object, action_trace() still reads data->synth_event and trace_synth() follows event->tp and tp->funcs; reclaiming that kmalloc object lets the attacker control those reads, giving a kernel-memory disclosure primitive.\nI:H - trace_synth() calls probe_func taken from the dangling event->tp->funcs, and a later action_data_destroy() does data->synth_event->ref-- on the freed object; spraying the reclaimed synth_event therefore yields a function-pointer hijack and a write primitive.\nA:H - trace_synth() does static_key_enabled(&tp->key) on event->tp from the freed synth_event the first time the leftover histogram fires, which oopses on a poisoned or unmapped pointer; the UAF is repeatable at will."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["kernel/trace/trace_events_hist.c", "kernel/trace/trace_events_synth.c", "kernel/trace/trace_synth.h"], "versions": [{"version": "4b147936fa509650beaf638b331573c23ba4d609", "lessThan": "381f543ed35c434d5b707369aa5dcd69ecf440af", "status": "affected", "versionType": "git"}, {"version": "4b147936fa509650beaf638b331573c23ba4d609", "lessThan": "4472579bd1c83708b6fe623c870cdf728e947205", "status": "affected", "versionType": "git"}, {"version": "4b147936fa509650beaf638b331573c23ba4d609", "lessThan": "23b4106e8b35823acc79e206c7745f55b9cfd78b", "status": "affected", "versionType": "git"}, {"version": "4b147936fa509650beaf638b331573c23ba4d609", "lessThan": "06e816bed499fe47f39f12044382cc5d064485fb", "status": "affected", "versionType": "git"}, {"version": "4b147936fa509650beaf638b331573c23ba4d609", "lessThan": "5597bb8db6855fcb97a67196d227fea359bcd81c", "status": "affected", "versionType": "git"}, {"version": "4b147936fa509650beaf638b331573c23ba4d609", "lessThan": "cf4e31d5da80fae4c9cdbe7af55b7c3ad213f0e4", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["kernel/trace/trace_events_hist.c", "kernel/trace/trace_events_synth.c", "kernel/trace/trace_synth.h"], "versions": [{"version": "4.17", "status": "affected"}, {"version": "0", "lessThan": "4.17", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.191", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.161", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.115", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.60", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.14", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3.1", "lessThanOrEqual": "7.3.*", "status": "unaffected", "versionType": "semver"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "6.1.191"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "6.6.161"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "6.12.115"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "6.18.60"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "7.2.14"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.17", "versionEndExcluding": "7.3.1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/381f543ed35c434d5b707369aa5dcd69ecf440af"}, {"url": "https://git.kernel.org/stable/c/4472579bd1c83708b6fe623c870cdf728e947205"}, {"url": "https://git.kernel.org/stable/c/23b4106e8b35823acc79e206c7745f55b9cfd78b"}, {"url": "https://git.kernel.org/stable/c/06e816bed499fe47f39f12044382cc5d064485fb"}, {"url": "https://git.kernel.org/stable/c/5597bb8db6855fcb97a67196d227fea359bcd81c"}, {"url": "https://git.kernel.org/stable/c/cf4e31d5da80fae4c9cdbe7af55b7c3ad213f0e4"}], "title": "tracing/histograms: Verify event_call identity when updating synth_event refcount", "x_generator": {"engine": "bippy-1.2.0"}}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["kernel/trace/trace_events_hist.c", "kernel/trace/trace_events_synth.c", "kernel/trace/trace_synth.h"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "381f543ed35c434d5b707369aa5dcd69ecf440af", "status": "affected", "version": "4b147936fa509650beaf638b331573c23ba4d609", "versionType": "git"}, {"lessThan": "4472579bd1c83708b6fe623c870cdf728e947205", "status": "affected", "version": "4b147936fa509650beaf638b331573c23ba4d609", "versionType": "git"}, {"lessThan": "23b4106e8b35823acc79e206c7745f55b9cfd78b", "status": "affected", "version": "4b147936fa509650beaf638b331573c23ba4d609", "versionType": "git"}, {"lessThan": "06e816bed499fe47f39f12044382cc5d064485fb", "status": "affected", "version": "4b147936fa509650beaf638b331573c23ba4d609", "versionType": "git"}, {"lessThan": "5597bb8db6855fcb97a67196d227fea359bcd81c", "status": "affected", "version": "4b147936fa509650beaf638b331573c23ba4d609", "versionType": "git"}, {"lessThan": "cf4e31d5da80fae4c9cdbe7af55b7c3ad213f0e4", "status": "affected", "version": "4b147936fa509650beaf638b331573c23ba4d609", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["kernel/trace/trace_events_hist.c", "kernel/trace/trace_events_synth.c", "kernel/trace/trace_synth.h"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "4.17"}, {"lessThan": "4.17", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.191", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.161", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.115", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.60", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.14", "versionType": "semver"}, {"lessThanOrEqual": "7.3.*", "status": "unaffected", "version": "7.3.1", "versionType": "semver"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing/histograms: Verify event_call identity when updating synth_event refcount\n\nIn event_hist_trigger_parse() and hist_unreg_all(), the histogram\nregistration and unregistration paths look up find_synth_event() using\ntrace_event_name(file->event_call) and adjust se->ref if a match is\nfound.\n\nBecause find_synth_event() only compares the event basename, registering\nor removing a histogram on a non-synthetic trace event whose basename\nmatches a synthetic event erroneously modifies the synthetic event's\nreference count. If a histogram is registered on the non-synthetic\nevent before the synthetic event is created and removed afterwards,\nse->ref is decremented without a matching increment, allowing the\nsynthetic event to be freed while an active histogram action still holds\na pointer to it.\n\nIntroduce find_synth_event_call() to verify that &se->call matches\nfile->event_call before adjusting se->ref."}], "id": "CVE-2026-99233", "lastModified": "2026-11-02T16:17:48.390", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-11-02T16:17:48.390", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/06e816bed499fe47f39f12044382cc5d064485fb"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/23b4106e8b35823acc79e206c7745f55b9cfd78b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/381f543ed35c434d5b707369aa5dcd69ecf440af"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/4472579bd1c83708b6fe623c870cdf728e947205"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/5597bb8db6855fcb97a67196d227fea359bcd81c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/cf4e31d5da80fae4c9cdbe7af55b7c3ad213f0e4"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}

{}