CVE-2026-98076
In the Linux kernel, the following vulnerability has been resolved:
tracing/probes: Fix use-after-free on field name/type of events with multiple probes
The fields of a probe-based dynamic event (kprobe, uprobe, eprobe and fprobe events) are created in traceprobe_define_arg_fields() by handing the probe_arg name/type strings to trace_define_field(), which only stores the pointers without copying. Those strings are owned by the trace_probe and are freed when that probe is removed.
An event can have several probes attached. The field list is defined only once, by the first probe that registers the event, but it is kept alive by any surviving sibling probe. Deleting just that first probe by symbol -
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frees A's args (trace_probe_cleanup() -> traceprobe_free_probe_arg()), but trace_probe_unlink() keeps the trace_probe_event because the probe list is not empty. The event call stays registered via B while its fields now reference freed memory. Any field lookup then reads it, e.g.
field->name references parg->name (kstrdup'd, freed with the probe) and, for array arguments, field->type references parg->fmt (kmalloc'd, freed with the probe) - the scalar type otherwise points at the static fmttype rodata, which is safe.
Have traceprobe_define_arg_fields() duplicate the name and type strings and anchor the copies on the trace_probe_event, which embeds the event call and outlives every individual probe; trace_probe_event_free() releases them.
The reproducer above triggers reliably; the field lookup and the delete both run under event_mutex, so this is a dangling reference after removal rather than a race.
The issue was found by the autokbug dynamic kernel fuzzer at Tencent Yunding Lab.
Detalles técnicos trazas, registros y código del informe original
# primary A: fields are defined from A's args echo 'p:kprobes/ev vfs_read a1=$arg1' > kprobe_events # append B: shares A's event call echo 'p:kprobes/ev vfs_write a1=$arg1' >> kprobe_events # delete only A (matched by symbol), B survives echo '-:kprobes/ev vfs_read' >> kprobe_events echo 'a1 == 1' > events/kprobes/ev/filter BUG: KASAN: slab-use-after-free in strcmp+0xa7/0xb0 Call Trace: strcmp trace_find_event_field parse_pred process_preds create_filter apply_event_filter event_filter_write
CVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.21%
- Percentil entre todas las CVEs puntuadas: 10
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
- https://git.kernel.org/stable/c/178ff2e011e21fbebdf57f5d58a408fe59136d82
- https://git.kernel.org/stable/c/38305e1b8b1ec27eef8f2d4e461e3b6c8624d494
- https://git.kernel.org/stable/c/411c9080a776577664531b4f7d3ee53b7a747ba8
- https://git.kernel.org/stable/c/68ae584169c7a41fc9bc4677c1d368983cf44b21
- https://git.kernel.org/stable/c/6d6118c17bc791594cbfd9cc4936ee21073b894a
- https://git.kernel.org/stable/c/86b7a239ec6b14a7544200ede85474c6f5526049
- https://git.kernel.org/stable/c/9379e193826f23876daccb3351fab89c87084ba3
- https://git.kernel.org/stable/c/a2510fcaad92b09b34574c97e8356234c6a84a9a
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-98076",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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{
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"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.4"
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{
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"version": "0",
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{
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{
"status": "unaffected",
"version": "5.15.222",
"versionType": "semver",
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{
"status": "unaffected",
"version": "6.1.189",
"versionType": "semver",
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{
"status": "unaffected",
"version": "6.6.158",
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{
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}
],
"published": "2026-09-25T11:17:36.963",
"references": [
{
"url": "https://git.kernel.org/stable/c/178ff2e011e21fbebdf57f5d58a408fe59136d82",
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Undergoing Analysis",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing/probes: Fix use-after-free on field name/type of events with multiple probes\n\nThe fields of a probe-based dynamic event (kprobe, uprobe, eprobe and\nfprobe events) are created in traceprobe_define_arg_fields() by handing\nthe probe_arg name/type strings to trace_define_field(), which only\nstores the pointers without copying. Those strings are owned by the\ntrace_probe and are freed when that probe is removed.\n\nAn event can have several probes attached. The field list is defined\nonly once, by the first probe that registers the event, but it is kept\nalive by any surviving sibling probe. Deleting just that first probe by\nsymbol -\n\n # primary A: fields are defined from A's args\n echo 'p:kprobes/ev vfs_read a1=$arg1' > kprobe_events\n # append B: shares A's event call\n echo 'p:kprobes/ev vfs_write a1=$arg1' >> kprobe_events\n # delete only A (matched by symbol), B survives\n echo '-:kprobes/ev vfs_read' >> kprobe_events\n\nfrees A's args (trace_probe_cleanup() -> traceprobe_free_probe_arg()),\nbut trace_probe_unlink() keeps the trace_probe_event because the probe\nlist is not empty. The event call stays registered via B while its\nfields now reference freed memory. Any field lookup then reads it, e.g.\n\n echo 'a1 == 1' > events/kprobes/ev/filter\n\n BUG: KASAN: slab-use-after-free in strcmp+0xa7/0xb0\n Call Trace:\n strcmp\n trace_find_event_field\n parse_pred\n process_preds\n create_filter\n apply_event_filter\n event_filter_write\n\nfield->name references parg->name (kstrdup'd, freed with the probe) and,\nfor array arguments, field->type references parg->fmt (kmalloc'd, freed\nwith the probe) - the scalar type otherwise points at the static\nfmttype rodata, which is safe.\n\nHave traceprobe_define_arg_fields() duplicate the name and type strings\nand anchor the copies on the trace_probe_event, which embeds the event\ncall and outlives every individual probe; trace_probe_event_free()\nreleases them.\n\nThe reproducer above triggers reliably; the field lookup and the delete\nboth run under event_mutex, so this is a dangling reference after\nremoval rather than a race.\n\nThe issue was found by the autokbug dynamic kernel fuzzer at Tencent\nYunding Lab."
}
],
"lastModified": "2026-10-03T11:18:29.080",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}