CVE-2026-74633
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix NULL pointer dereference in module event cache removal
A module-only event filter such as ":mod:foo" is cached with a NULL event_mod->match when foo has not been loaded. If a later write tries to remove a specific match from the same module, remove_cache_mod() passes the NULL cached match to strcmp(), causing a NULL pointer dereference.
The issue can be reproduced from userspace:
The second write must be a concatenation (">>") to not include O_TRUNC as that would cause ftrace_clear_events() to clear the cached modules lines.
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The crash was reproduced on x86_64 QEMU while KUnit workers contended on the event tracing path:
Check event_mod->match before comparing it, consistent with the existing NULL checks for the cached system and event fields. The mismatched removal continues to return -EINVAL; a broad cached module filter is removed with "!:mod:<module>".
Detalles técnicos trazas, registros y código del informe original
echo ':mod:trace_events_kunit_missing' > /sys/kernel/tracing/set_event echo '!foo_bar:mod:trace_events_kunit_missing' >> /sys/kernel/tracing/set_event BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode RIP: 0010:strcmp+0x10/0x30 Call Trace: __ftrace_set_clr_event_nolock+0x373/0x4a0 ftrace_set_clr_event+0xf0/0x180 ftrace_event_write+0xdf/0x110 vfs_write+0xf6/0x440 ksys_write+0x68/0xe0 do_syscall_64+0xf9/0x540 entry_SYSCALL_64_after_hwframe+0x77/0x7f
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
JSON original (NVD)
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{
"id": "CVE-2026-74633",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "b355247df104ef6644288884afd2c08b7bf49897",
"lessThan": "152a00440dc6ef62c6e4cf9bd881a7e6bb81fda9",
"versionType": "git"
},
{
"status": "affected",
"version": "b355247df104ef6644288884afd2c08b7bf49897",
"lessThan": "ad4e9dd5fec7a322a471ff36fb9c76214e3c6992",
"versionType": "git"
},
{
"status": "affected",
"version": "b355247df104ef6644288884afd2c08b7bf49897",
"lessThan": "b69859204d4db3acd86c1c2dadcef0d77b451933",
"versionType": "git"
}
],
"programFiles": [
"kernel/trace/trace_events.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.14"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.14",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.18.45",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.9",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"kernel/trace/trace_events.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-08-22T16:16:36.380",
"references": [
{
"url": "https://git.kernel.org/stable/c/152a00440dc6ef62c6e4cf9bd881a7e6bb81fda9",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/ad4e9dd5fec7a322a471ff36fb9c76214e3c6992",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/b69859204d4db3acd86c1c2dadcef0d77b451933",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix NULL pointer dereference in module event cache removal\n\nA module-only event filter such as \":mod:foo\" is cached with a NULL\nevent_mod->match when foo has not been loaded. If a later write tries to\nremove a specific match from the same module, remove_cache_mod() passes\nthe NULL cached match to strcmp(), causing a NULL pointer dereference.\n\nThe issue can be reproduced from userspace:\n\n echo ':mod:trace_events_kunit_missing' > /sys/kernel/tracing/set_event\n echo '!foo_bar:mod:trace_events_kunit_missing' >> /sys/kernel/tracing/set_event\n\nThe second write must be a concatenation (\">>\") to not include O_TRUNC as\nthat would cause ftrace_clear_events() to clear the cached modules lines.\n\nThe crash was reproduced on x86_64 QEMU while KUnit workers contended on\nthe event tracing path:\n\n BUG: kernel NULL pointer dereference, address: 0000000000000000\n #PF: supervisor read access in kernel mode\n RIP: 0010:strcmp+0x10/0x30\n Call Trace:\n __ftrace_set_clr_event_nolock+0x373/0x4a0\n ftrace_set_clr_event+0xf0/0x180\n ftrace_event_write+0xdf/0x110\n vfs_write+0xf6/0x440\n ksys_write+0x68/0xe0\n do_syscall_64+0xf9/0x540\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nCheck event_mod->match before comparing it, consistent with the existing\nNULL checks for the cached system and event fields. The mismatched removal\ncontinues to return -EINVAL; a broad cached module filter is removed with\n\"!:mod:<module>\"."
}
],
"lastModified": "2026-08-22T16:16:36.380",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}