FKIE_CVE-2026-89746
Vulnerability from fkie_nvd - Published: 2026-09-11 20:20 - Updated: 2026-09-14 13:19
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix use-after-free with same-name named triggers
When two hist triggers on different events are registered with the same
name=, the second one reuses the first as named_data. Both are added to
tr->hist_vars by save_hist_vars() during event_hist_trigger_parse(),
because save_hist_vars() is called before event_trigger_register() while
the named reuse is only detected later, in hist_register_trigger().
In the named-data branch hist_register_trigger() then frees the second
histogram's hist_data via destroy_hist_data(), but never removes its
tr->hist_vars list entry, leaving a dangling pointer and leaking the
trace_array reference it holds.
A later hist trigger that references a variable makes find_var_file()
walk tr->hist_vars and dereference the freed hist_data. The bug is
reproducible from userspace by writing three hist triggers to tracefs:
cd /sys/kernel/tracing
echo 'hist:keys=common_pid:x=common_pid:name=mh' > events/sched/sched_switch/trigger
echo 'hist:keys=common_pid:x=common_pid:name=mh' > events/sched/sched_process_fork/trigger
echo 'hist:keys=common_pid:vals=$x' > events/sched/sched_process_exit/trigger
The third write panics the kernel:
BUG: KASAN: slab-use-after-free in find_var_file.part.0+0x272/0x290
Read of size 8 at addr ffff888001f8a0e0 by task sh/1
CPU: 1 UID: 0 PID: 1 Comm: sh Tainted: G D N
Call Trace:
find_var_file.part.0
find_event_var
parse_atom
parse_expr
__create_val_field
event_hist_trigger_parse
trigger_process_regex
event_trigger_write
vfs_write
ksys_write
do_syscall_64
entry_SYSCALL_64_after_hwframe
Allocated by task 1:
event_hist_trigger_parse
Freed by task 1:
hist_register_trigger+0x618/0xa30
event_hist_trigger_parse
The buggy address belongs to freed 2048-byte region
Oops: general protection fault ... RIP: find_var_file.part.0
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
Fix by removing the hist_data from tr->hist_vars and releasing the
trace_array reference in the named-data branch of hist_register_trigger()
before freeing the hist_data.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"kernel/trace/trace_events_hist.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "441aa6742dff70297b5f64533a07a6189a026e91",
"status": "affected",
"version": "5ae1b18f05ee2b849dc03b6c15d7da0c1c6efa77",
"versionType": "git"
},
{
"lessThan": "3a8534664426c071c2dfb5b4ffa36b18a2abfd79",
"status": "affected",
"version": "43b254d46c740bf9dbe65709afa021dd726dfa99",
"versionType": "git"
},
{
"lessThan": "477d762be4b0ffaf01429ccd88859e93b0ec28cc",
"status": "affected",
"version": "435d2964af815aae456db554c62963b4515f19d0",
"versionType": "git"
},
{
"lessThan": "b1a49c22de01faf176d44e5caa765e237353a579",
"status": "affected",
"version": "6f86bdeab633a56d5c6dccf1a2c5989b6a5e323e",
"versionType": "git"
},
{
"lessThan": "83d1ae0406d8eade219a81b401e201702dd9dc55",
"status": "affected",
"version": "6f86bdeab633a56d5c6dccf1a2c5989b6a5e323e",
"versionType": "git"
},
{
"lessThan": "a7318172aa332a161fb9618286e64454c827f8fd",
"status": "affected",
"version": "6f86bdeab633a56d5c6dccf1a2c5989b6a5e323e",
"versionType": "git"
},
{
"status": "affected",
"version": "f1ae50cfb818ce1ac7a674406dfadb7653e2552d",
"versionType": "git"
},
{
"lessThan": "6.1.188",
"status": "affected",
"version": "6.1.130",
"versionType": "semver"
},
{
"lessThan": "6.6.157",
"status": "affected",
"version": "6.6.81",
"versionType": "semver"
},
{
"lessThan": "6.12.109",
"status": "affected",
"version": "6.12.18",
"versionType": "semver"
},
{
"lessThan": "6.14",
"status": "affected",
"version": "6.13.6",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"kernel/trace/trace_events_hist.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.14"
},
{
"lessThan": "6.14",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.188",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.157",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.109",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.50",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3-rc1",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix use-after-free with same-name named triggers\n\nWhen two hist triggers on different events are registered with the same\nname=, the second one reuses the first as named_data. Both are added to\ntr-\u003ehist_vars by save_hist_vars() during event_hist_trigger_parse(),\nbecause save_hist_vars() is called before event_trigger_register() while\nthe named reuse is only detected later, in hist_register_trigger().\n\nIn the named-data branch hist_register_trigger() then frees the second\nhistogram\u0027s hist_data via destroy_hist_data(), but never removes its\ntr-\u003ehist_vars list entry, leaving a dangling pointer and leaking the\ntrace_array reference it holds.\n\nA later hist trigger that references a variable makes find_var_file()\nwalk tr-\u003ehist_vars and dereference the freed hist_data. The bug is\nreproducible from userspace by writing three hist triggers to tracefs:\n\n cd /sys/kernel/tracing\n echo \u0027hist:keys=common_pid:x=common_pid:name=mh\u0027 \u003e events/sched/sched_switch/trigger\n echo \u0027hist:keys=common_pid:x=common_pid:name=mh\u0027 \u003e events/sched/sched_process_fork/trigger\n echo \u0027hist:keys=common_pid:vals=$x\u0027 \u003e events/sched/sched_process_exit/trigger\n\nThe third write panics the kernel:\n\n BUG: KASAN: slab-use-after-free in find_var_file.part.0+0x272/0x290\n Read of size 8 at addr ffff888001f8a0e0 by task sh/1\n CPU: 1 UID: 0 PID: 1 Comm: sh Tainted: G D N\n Call Trace:\n find_var_file.part.0\n find_event_var\n parse_atom\n parse_expr\n __create_val_field\n event_hist_trigger_parse\n trigger_process_regex\n event_trigger_write\n vfs_write\n ksys_write\n do_syscall_64\n entry_SYSCALL_64_after_hwframe\n Allocated by task 1:\n event_hist_trigger_parse\n Freed by task 1:\n hist_register_trigger+0x618/0xa30\n event_hist_trigger_parse\n The buggy address belongs to freed 2048-byte region\n Oops: general protection fault ... RIP: find_var_file.part.0\n Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b\n\nFix by removing the hist_data from tr-\u003ehist_vars and releasing the\ntrace_array reference in the named-data branch of hist_register_trigger()\nbefore freeing the hist_data."
}
],
"id": "CVE-2026-89746",
"lastModified": "2026-09-14T13:19:23.350",
"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": "2026-09-11T20:20:05.373",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/3a8534664426c071c2dfb5b4ffa36b18a2abfd79"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/441aa6742dff70297b5f64533a07a6189a026e91"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/477d762be4b0ffaf01429ccd88859e93b0ec28cc"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/83d1ae0406d8eade219a81b401e201702dd9dc55"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/a7318172aa332a161fb9618286e64454c827f8fd"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/b1a49c22de01faf176d44e5caa765e237353a579"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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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
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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.
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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