CVE-2026-74711 (GCVE-0-2026-74711)
Vulnerability from cvelistv5
Published
2026-08-22 15:33
Modified
2026-08-25 05:41
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
hwmon: (pmbus) Fix type confusion in notification logic
Sashiko reports:
At the start of the loop in pmbus_notify(), the code unconditionally casts
every attribute to a struct sensor_device_attribute:
drivers/hwmon/pmbus/pmbus_core.c:pmbus_notify() {
for (i = 0; i < data->num_attributes; i++) {
struct device_attribute *da = to_dev_attr(data->group.attrs[i]);
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
int index = attr->index;
...
}
However, data->group.attrs can contain other types like struct
pmbus_samples_reg or struct pmbus_sensor, which only embed a base
struct device_attribute.
If da is a struct pmbus_samples_reg, dev_attr is the last member. Casting
it to struct sensor_device_attribute and reading the index field appears
to access memory past the end of the allocation, which might trigger a
slab-out-of-bounds read.
Additionally, if da is a struct pmbus_sensor, casting it causes the index
field to overlap with the page, phase, and reg fields. Could this produce
a garbage mask on little-endian systems that spuriously matches the target
reg, page, and flags during an alert?
Fix the problem by using struct sensor_device_attr in struct pmbus_sensor
and struct pmbus_label. Since those attributes never trigger a
notification, set the value of attr->index to -1 for them. Use this value
to distinguish from boolean attributes which _can_ trigger a notification
and use the index field to encode mask, page, and register values.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/hwmon/pmbus/pmbus_core.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "821f6416e69782fa662aff94b5ea52c943042790",
"status": "affected",
"version": "f469bde9afd136598a0c4edc054296e6046f90ee",
"versionType": "git"
},
{
"lessThan": "0b121de89a99c54bcf516999b04e8531c84f08d5",
"status": "affected",
"version": "f469bde9afd136598a0c4edc054296e6046f90ee",
"versionType": "git"
},
{
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"status": "affected",
"version": "f469bde9afd136598a0c4edc054296e6046f90ee",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/hwmon/pmbus/pmbus_core.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.4"
},
{
"lessThan": "6.4",
"status": "unaffected",
"version": "0",
"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": "6.18.45",
"versionStartIncluding": "6.4",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.9",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "6.4",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nhwmon: (pmbus) Fix type confusion in notification logic\n\nSashiko reports:\n\nAt the start of the loop in pmbus_notify(), the code unconditionally casts\nevery attribute to a struct sensor_device_attribute:\n\ndrivers/hwmon/pmbus/pmbus_core.c:pmbus_notify() {\n for (i = 0; i \u003c data-\u003enum_attributes; i++) {\n struct device_attribute *da = to_dev_attr(data-\u003egroup.attrs[i]);\n struct sensor_device_attribute *attr = to_sensor_dev_attr(da);\n int index = attr-\u003eindex;\n...\n}\n\nHowever, data-\u003egroup.attrs can contain other types like struct\npmbus_samples_reg or struct pmbus_sensor, which only embed a base\nstruct device_attribute.\n\nIf da is a struct pmbus_samples_reg, dev_attr is the last member. Casting\nit to struct sensor_device_attribute and reading the index field appears\nto access memory past the end of the allocation, which might trigger a\nslab-out-of-bounds read.\n\nAdditionally, if da is a struct pmbus_sensor, casting it causes the index\nfield to overlap with the page, phase, and reg fields. Could this produce\na garbage mask on little-endian systems that spuriously matches the target\nreg, page, and flags during an alert?\n\nFix the problem by using struct sensor_device_attr in struct pmbus_sensor\nand struct pmbus_label. Since those attributes never trigger a\nnotification, set the value of attr-\u003eindex to -1 for them. Use this value\nto distinguish from boolean attributes which _can_ trigger a notification\nand use the index field to encode mask, page, and register values."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.4,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The flawed pmbus_notify() runs only in the PMBus SMBALERT threaded IRQ handler after the host kernel reads fault status from an on-board I2C/SMBus PSU/PMIC; reaching it requires local presence on a system exposing that bus, not a remote network protocol.\nAC:L - Once SMBALERT IRQ handling is enabled, the type confusion and slab out-of-bounds read occur deterministically on every alert while iterating attributes; an attacker can repeatedly provoke PSU/PMIC faults (e.g., sustained CPU/GPU load) rather than depend on uncontrollable timing.\nPR:N - No special kernel capability is needed to hit the IRQ path\u2014any unprivileged local process that can drive hardware into an overcurrent/overtemp fault (cloud tenant, factory HMI user, embedded service account) can cause SMBALERT and exercise the bug.\nUI:N - Exploitation is driven by attacker-induced or naturally occurring PMBus fault interrupts and does not require any victim to open files, click prompts, or perform other interactive actions.\nS:U - Impact is confined to kernel memory safety within the host OS security authority; it is not a VM escape, IOMMU/DMA boundary bypass, or other cross-authority compromise.\nC:H - Casting pmbus_samples_reg device attributes to sensor_device_attribute reads attr-\u003eindex past the object end (slab out-of-bounds), and pmbus_sensor casts reinterpret adjacent page/phase/reg bytes as an index, enabling kernel heap metadata or pointer disclosure.\nI:H - This is a type confusion in kernel notification logic: mis-decoded indices can spuriously satisfy reg/page/mask checks and drive sysfs_notify/uevent on unintended attributes, a memory-safety defect with potential for further corruption primitives.\nA:H - The out-of-bounds slab read and malformed attribute matching in interrupt context can trigger KASAN/BUG faults or kernel oops/panic when alerts fire on production systems with PMBus SMBALERT wired."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-25T05:41:53.683Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/821f6416e69782fa662aff94b5ea52c943042790"
},
{
"url": "https://git.kernel.org/stable/c/0b121de89a99c54bcf516999b04e8531c84f08d5"
},
{
"url": "https://git.kernel.org/stable/c/59bd68ab05a8f9c9a60b6ec44682084184803ff4"
}
],
"title": "hwmon: (pmbus) Fix type confusion in notification logic",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74711",
"datePublished": "2026-08-22T15:33:07.779Z",
"dateReserved": "2026-08-15T05:44:03.928Z",
"dateUpdated": "2026-08-25T05:41:53.683Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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