CVE-2026-99238 (GCVE-0-2026-99238)
Vulnerability from cvelistv5 – Published: 2026-11-02 16:06 – Updated: 2026-11-02 16:06
VLAI
EPSS
VEX
Title
tracing: Hold trace_types_lock when updating modules in persistent instances
Summary
In the Linux kernel, the following vulnerability has been resolved:
tracing: Hold trace_types_lock when updating modules in persistent instances
trace_module_record() walks ftrace_trace_arrays from the module notifier
without trace_types_lock. A concurrent rmdir of an instance removes it
from the list and frees it under that lock, so a module load or unload
can walk into a freed trace_array.
Severity
7.8 (High)
Assigner
References
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
5f3719f697c3fdfae5cd6805f10ac7a04b0f4e43 , < 57408eac99b0d8a005796346d317d31f0ca4e07a
(git)
Affected: 5f3719f697c3fdfae5cd6805f10ac7a04b0f4e43 , < dab2bd4d67ad5eaa95019a9511f8d379401b5021 (git) Affected: 5f3719f697c3fdfae5cd6805f10ac7a04b0f4e43 , < 244c442f54601a24c86ad90572bf36fc3df41c5e (git) |
guessed | |
| Linux | Linux |
Affected:
6.15
Unaffected: 0 , < 6.15 (semver) Unaffected: 6.18.60 , ≤ 6.18.* (semver) Unaffected: 7.2.14 , ≤ 7.2.* (semver) Unaffected: 7.3.1 , ≤ 7.3.* (semver) |
guessed |
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"versions": [
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"version": "6.15"
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"version": "0",
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"status": "unaffected",
"version": "7.3.1",
"versionType": "semver"
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}
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"cpeApplicability": [
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"nodes": [
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"cpeMatch": [
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"versionStartIncluding": "6.15",
"vulnerable": true
}
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"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Hold trace_types_lock when updating modules in persistent instances\n\ntrace_module_record() walks ftrace_trace_arrays from the module notifier\nwithout trace_types_lock. A concurrent rmdir of an instance removes it\nfrom the list and frees it under that lock, so a module load or unload\ncan walk into a freed trace_array."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - trace_module_record() is reached only from trace_module_notify() on MODULE_STATE_COMING/GOING via load_module()-\u003eprepare_coming_module() or delete_module(), i.e. local finit_module/init_module/delete_module or __sock_create()\u0027s request_module(\"net-pf-%d\"). The concurrent free is rmdir(2) on tracefs instances (tracefs_syscall_rmdir()-\u003einstance_rmdir()). No protocol message carries the list pointer.\nAC:L - The attacker mkdir()s an instance, then concurrently rmdir()s it so __remove_instance() list_del()+kfree()s the trace_array while another thread loads or unloads a module and trace_module_record() walks ftrace_trace_arrays unlocked. They drive both sides and can retry; a boot/persistent instance is unnecessary because the walk visits every trace_array before checking TRACE_ARRAY_FL_BOOT.\nPR:L - instance_mkdir()/instance_rmdir() (via tracefs_syscall_rmdir) check only VFS DAC on the 0750 instances directory and LOCKDOWN_TRACEFS, not capable(). tracefs_parse_param() uid=/gid= makes a non-root owner of that directory. The COMING notifier also runs after __sock_create()\u0027s request_module(\"net-pf-%d\"), which is not gated by CAP_SYS_MODULE.\nUI:N - The attacker mkdir/rmdir their own /sys/kernel/tracing/instances/\u003cname\u003e and starts the module load or unload (socket() autoload, finit_module, or delete_module) on their own threads. No other user must mount media, open a file, or confirm the action.\nS:U - __remove_instance() kfree()s a host-kernel struct trace_array that trace_module_record() still walks on ftrace_trace_arrays. The resulting heap corruption stays in the tracing subsystem on that host and does not cross a VM, IOMMU, or guest/host boundary.\nC:H - After __remove_instance() kfree()s the kzalloc\u0027d trace_array, trace_module_record() still reads tr-\u003eflags and list_for_each_entry follows tr-\u003elist.next. Reclaiming that object lets the attacker control those fields and the later tr-\u003escratch/tr-\u003emodule_delta pointers, which is a use-after-free kernel read.\nI:H - If the reclaimed object\u0027s flags include TRACE_ARRAY_FL_BOOT, save_mod() writes mod-\u003ename and mod_addr through attacker-controlled tr-\u003escratch; if TRACE_ARRAY_FL_LAST_BOOT is set, make_mod_delta() writes tr-\u003emodule_delta-\u003edelta[]. That use-after-free write is a kernel heap and control-flow primitive.\nA:H - list_for_each_entry on the kfree\u0027d trace_array in trace_module_record(), or save_mod()/make_mod_delta() dereferencing stale tr-\u003escratch, oopses or panics the kernel. The attacker can repeat the rmdir-versus-module-notifier race until that crash hits."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-11-02T16:06:42.810Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
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"url": "https://git.kernel.org/stable/c/57408eac99b0d8a005796346d317d31f0ca4e07a"
},
{
"url": "https://git.kernel.org/stable/c/dab2bd4d67ad5eaa95019a9511f8d379401b5021"
},
{
"url": "https://git.kernel.org/stable/c/244c442f54601a24c86ad90572bf36fc3df41c5e"
}
],
"title": "tracing: Hold trace_types_lock when updating modules in persistent instances",
"x_generator": {
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"assignerShortName": "Linux",
"cveId": "CVE-2026-99238",
"datePublished": "2026-11-02T16:06:42.810Z",
"dateReserved": "2026-09-25T10:25:14.403Z",
"dateUpdated": "2026-11-02T16:06:42.810Z",
"state": "PUBLISHED"
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"version": "0",
"versionType": "semver"
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{
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"version": "7.2.14",
"versionType": "semver"
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{
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"status": "unaffected",
"version": "7.3.1",
"versionType": "semver"
}
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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],
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Hold trace_types_lock when updating modules in persistent instances\n\ntrace_module_record() walks ftrace_trace_arrays from the module notifier\nwithout trace_types_lock. A concurrent rmdir of an instance removes it\nfrom the list and frees it under that lock, so a module load or unload\ncan walk into a freed trace_array."
}
],
"id": "CVE-2026-99238",
"lastModified": "2026-11-02T16:17:49.380",
"metrics": {
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{
"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": "2026-11-02T16:17:49.380",
"references": [
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/244c442f54601a24c86ad90572bf36fc3df41c5e"
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/57408eac99b0d8a005796346d317d31f0ca4e07a"
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"url": "https://git.kernel.org/stable/c/dab2bd4d67ad5eaa95019a9511f8d379401b5021"
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"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
}
}
}
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Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
How durations are calculated
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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
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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.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.