CVE-2026-74636 (GCVE-0-2026-74636)
Vulnerability from cvelistv5 – Published: 2026-08-22 15:32 – Updated: 2026-08-22 15:32
VLAI
EPSS
VEX
Title
tracing: Fix race between update_event_fields and, event_define_fields
Summary
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix race between update_event_fields and, event_define_fields
The following sequence may leads race between event_define_fields()
and update_event_fields():
CPU0 (loads module A) CPU1 (loads module B)
=============================== ===============================
load_module(A) load_module(B)
notifier_call_chain notifier_call_chain
trace_module_notify trace_module_notify
mutex_lock(&event_mutex) trace_event_update_all()
trace_module_add_events(A) down_write(&trace_event_sem)
__register_event(call_A)
__add_event_to_tracers(call_A)
event_define_fields(call_A)
for each f: list_for_each_entry(field,
list_add(&f->link, &class->fields, link)
&class->fields) field = class->fields->next;
Where access to the class->fields is not protected by the event_mutex in
trace_event_update_all().
This produces the following panic:
Unable to handle kernel access ... at virtual address 0000000000000018
pc : update_event_fields+0xf8/0x368
Call trace:
update_event_fields+0xf8/0x368
trace_event_update_all+0x7c/0x2b4
trace_module_notify+0x4c/0x1dc
notifier_call_chain+0x84/0x168
blocking_notifier_call_chain_robust+0x64/0xd4
load_module+0x10c8/0x123c
__arm64_sys_finit_module+0x230/0x31c
Fix by taking event_mutex in trace_event_update_all() before
trace_event_sem.
Severity
No CVSS data available.
Assigner
References
7 references
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
7c6bd60999f32138e3b73fd97ea11ef47a94de25 , < 4e39f7b4d9d36508c53e89e6cbc640728df870b5
(git)
Affected: b3bc8547d3be60898818885f5bf22d0a62e2eb48 , < a30d421468300b1e7b2f233136aeb2db8013f555 (git) Affected: b3bc8547d3be60898818885f5bf22d0a62e2eb48 , < e5f1d301b4bdaa4206db251fdc691f623162b0a8 (git) Affected: b3bc8547d3be60898818885f5bf22d0a62e2eb48 , < fdeb190b0905a6aaed1e5d6adfb8613214748d7d (git) Affected: b3bc8547d3be60898818885f5bf22d0a62e2eb48 , < ed49684e69f846bf50b5050651ccdb87cfd152c0 (git) Affected: b3bc8547d3be60898818885f5bf22d0a62e2eb48 , < f128740f39ab28d1f4ad5bdd10f3e117eec0c374 (git) Affected: b3bc8547d3be60898818885f5bf22d0a62e2eb48 , < c3730b8373bb5059d735509b9e6a00d7eb337d7c (git) Affected: 55defdf935fab9f2989a197aae1042c082d9a343 (git) Affected: 0c53a5c80e6e286733381a1d9f255ba4039e2e45 (git) Affected: 5.15.33 , < 5.15.216 (semver) Affected: 5.16.19 , < 5.17 (semver) Affected: 5.17.2 , < 5.18 (semver) |
guessed | |
| Linux | Linux |
Affected:
5.18
Unaffected: 0 , < 5.18 (semver) Unaffected: 5.15.216 , ≤ 5.15.* (semver) Unaffected: 6.1.183 , ≤ 6.1.* (semver) Unaffected: 6.6.152 , ≤ 6.6.* (semver) Unaffected: 6.12.104 , ≤ 6.12.* (semver) Unaffected: 6.18.45 , ≤ 6.18.* (semver) Unaffected: 7.1.9 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix) |
guessed |
{
"containers": {
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"programFiles": [
"kernel/trace/trace_events.c"
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{
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"versionType": "semver"
},
{
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"status": "affected",
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"versionType": "semver"
}
]
},
{
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"product": "Linux",
"programFiles": [
"kernel/trace/trace_events.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.18"
},
{
"lessThan": "5.18",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.152",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.104",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.45",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.9",
"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": "5.15.216",
"versionStartIncluding": "5.15.33",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.183",
"versionStartIncluding": "5.18",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.152",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.104",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.45",
"versionStartIncluding": "5.18",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.9",
"versionStartIncluding": "5.18",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "5.18",
"vulnerable": true
},
{
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"versionStartIncluding": "5.16.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "5.17.2",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix race between update_event_fields and, event_define_fields\n\nThe following sequence may leads race between event_define_fields()\nand update_event_fields():\n\n CPU0 (loads module A) CPU1 (loads module B)\n =============================== ===============================\n load_module(A) load_module(B)\n notifier_call_chain notifier_call_chain\n trace_module_notify trace_module_notify\n mutex_lock(\u0026event_mutex) trace_event_update_all()\n trace_module_add_events(A) down_write(\u0026trace_event_sem)\n __register_event(call_A)\n __add_event_to_tracers(call_A)\n event_define_fields(call_A)\n for each f: list_for_each_entry(field,\n list_add(\u0026f-\u003elink, \u0026class-\u003efields, link)\n \u0026class-\u003efields) field = class-\u003efields-\u003enext;\n\nWhere access to the class-\u003efields is not protected by the event_mutex in\ntrace_event_update_all().\n\nThis produces the following panic:\n Unable to handle kernel access ... at virtual address 0000000000000018\n pc : update_event_fields+0xf8/0x368\n Call trace:\n update_event_fields+0xf8/0x368\n trace_event_update_all+0x7c/0x2b4\n trace_module_notify+0x4c/0x1dc\n notifier_call_chain+0x84/0x168\n blocking_notifier_call_chain_robust+0x64/0xd4\n load_module+0x10c8/0x123c\n __arm64_sys_finit_module+0x230/0x31c\n\nFix by taking event_mutex in trace_event_update_all() before\ntrace_event_sem."
}
],
"providerMetadata": {
"dateUpdated": "2026-08-22T15:32:16.026Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/4e39f7b4d9d36508c53e89e6cbc640728df870b5"
},
{
"url": "https://git.kernel.org/stable/c/a30d421468300b1e7b2f233136aeb2db8013f555"
},
{
"url": "https://git.kernel.org/stable/c/e5f1d301b4bdaa4206db251fdc691f623162b0a8"
},
{
"url": "https://git.kernel.org/stable/c/fdeb190b0905a6aaed1e5d6adfb8613214748d7d"
},
{
"url": "https://git.kernel.org/stable/c/ed49684e69f846bf50b5050651ccdb87cfd152c0"
},
{
"url": "https://git.kernel.org/stable/c/f128740f39ab28d1f4ad5bdd10f3e117eec0c374"
},
{
"url": "https://git.kernel.org/stable/c/c3730b8373bb5059d735509b9e6a00d7eb337d7c"
}
],
"title": "tracing: Fix race between update_event_fields and, event_define_fields",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74636",
"datePublished": "2026-08-22T15:32:16.026Z",
"dateReserved": "2026-08-15T05:44:03.922Z",
"dateUpdated": "2026-08-22T15:32:16.026Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-74636",
"date": "2026-08-29",
"epss": "0.00173",
"percentile": "0.06791"
},
"microsoft_vex": {
"current_release_date": "2026-08-24T14:45:13.000Z",
"cve": "CVE-2026-74636",
"id": "msrc_CVE-2026-74636",
"initial_release_date": "2026-08-24T01:11:43.000Z",
"product_status:known_affected": "1",
"source": "Microsoft CSAF VEX",
"status": "final",
"title": "tracing: Fix race between update_event_fields and, event_define_fields",
"url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74636.json",
"version": "2"
},
"nvd": "{\"cve\":{\"id\":\"CVE-2026-74636\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-22T16:16:36.750\",\"lastModified\":\"2026-08-22T16:16:36.750\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\ntracing: Fix race between update_event_fields and, event_define_fields\\n\\nThe following sequence may leads race between event_define_fields()\\nand update_event_fields():\\n\\n CPU0 (loads module A) CPU1 (loads module B)\\n =============================== ===============================\\n load_module(A) load_module(B)\\n notifier_call_chain notifier_call_chain\\n trace_module_notify trace_module_notify\\n mutex_lock(\u0026event_mutex) trace_event_update_all()\\n trace_module_add_events(A) down_write(\u0026trace_event_sem)\\n __register_event(call_A)\\n __add_event_to_tracers(call_A)\\n event_define_fields(call_A)\\n for each f: list_for_each_entry(field,\\n list_add(\u0026f-\u003elink, \u0026class-\u003efields, link)\\n \u0026class-\u003efields) field = class-\u003efields-\u003enext;\\n\\nWhere access to the class-\u003efields is not protected by the event_mutex in\\ntrace_event_update_all().\\n\\nThis produces the following panic:\\n Unable to handle kernel access ... at virtual address 0000000000000018\\n pc : update_event_fields+0xf8/0x368\\n Call trace:\\n update_event_fields+0xf8/0x368\\n trace_event_update_all+0x7c/0x2b4\\n trace_module_notify+0x4c/0x1dc\\n notifier_call_chain+0x84/0x168\\n blocking_notifier_call_chain_robust+0x64/0xd4\\n load_module+0x10c8/0x123c\\n __arm64_sys_finit_module+0x230/0x31c\\n\\nFix by taking event_mutex in trace_event_update_all() before\\ntrace_event_sem.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"kernel/trace/trace_events.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"7c6bd60999f32138e3b73fd97ea11ef47a94de25\",\"lessThan\":\"4e39f7b4d9d36508c53e89e6cbc640728df870b5\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"b3bc8547d3be60898818885f5bf22d0a62e2eb48\",\"lessThan\":\"a30d421468300b1e7b2f233136aeb2db8013f555\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"b3bc8547d3be60898818885f5bf22d0a62e2eb48\",\"lessThan\":\"e5f1d301b4bdaa4206db251fdc691f623162b0a8\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"b3bc8547d3be60898818885f5bf22d0a62e2eb48\",\"lessThan\":\"fdeb190b0905a6aaed1e5d6adfb8613214748d7d\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"b3bc8547d3be60898818885f5bf22d0a62e2eb48\",\"lessThan\":\"ed49684e69f846bf50b5050651ccdb87cfd152c0\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"b3bc8547d3be60898818885f5bf22d0a62e2eb48\",\"lessThan\":\"f128740f39ab28d1f4ad5bdd10f3e117eec0c374\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"b3bc8547d3be60898818885f5bf22d0a62e2eb48\",\"lessThan\":\"c3730b8373bb5059d735509b9e6a00d7eb337d7c\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"55defdf935fab9f2989a197aae1042c082d9a343\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"0c53a5c80e6e286733381a1d9f255ba4039e2e45\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"5.15.33\",\"lessThan\":\"5.15.216\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"5.16.19\",\"lessThan\":\"5.17\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"5.17.2\",\"lessThan\":\"5.18\",\"versionType\":\"semver\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"kernel/trace/trace_events.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.18\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.18\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.216\",\"lessThanOrEqual\":\"5.15.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.183\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.152\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.104\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.45\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.9\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/4e39f7b4d9d36508c53e89e6cbc640728df870b5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/a30d421468300b1e7b2f233136aeb2db8013f555\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c3730b8373bb5059d735509b9e6a00d7eb337d7c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e5f1d301b4bdaa4206db251fdc691f623162b0a8\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ed49684e69f846bf50b5050651ccdb87cfd152c0\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f128740f39ab28d1f4ad5bdd10f3e117eec0c374\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/fdeb190b0905a6aaed1e5d6adfb8613214748d7d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
"redhat_vex": {
"aggregate_severity": "Low",
"current_release_date": "2026-08-24T14:36:28+00:00",
"cve": "CVE-2026-74636",
"id": "CVE-2026-74636",
"initial_release_date": "2026-08-22T00:00:00+00:00",
"product_status:known_affected": "198",
"product_status:known_not_affected": "76",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: tracing: Fix race between update_event_fields and, event_define_fields",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74636.json",
"version": "3"
}
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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