CVE-2026-64205 (GCVE-0-2026-64205)
Vulnerability from cvelistv5
Published
2026-07-20 16:27
Modified
2026-08-17 04:51
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
i2c: i801: fix hardware state machine corruption in error path
A severe livelock and subsequent Hung Task panic were observed in the
i2c-i801 driver during concurrent Fuzzing. The crash is caused by an
unconditional hardware register cleanup in the error handling path of
i801_access().
When i801_check_pre() fails (e.g., returning -EBUSY because the SMBus
controller is actively used by BIOS/ACPI), the kernel does not actually
acquire the hardware ownership. However, the code jumps to the 'out'
label and executes:
iowrite8(SMBHSTSTS_INUSE_STS | STATUS_FLAGS, SMBHSTSTS(priv));
This forcefully clears the INUSE_STS lock and resets the hardware status
flags without owning the controller. Doing so interrupts ongoing BIOS/ACPI
transactions and totally corrupts the SMBus hardware state machine.
Consequently, all subsequent i801_access() calls fail at the pre-check
stage, triggering an endless stream of "SMBus is busy, can't use it!"
error logs. Over a slow serial console, this printk flood monopolizes
the CPU (Console Livelock), starving other processes trying to acquire
the mmap_lock down_read semaphore, ultimately triggering the hung task
watchdog.
Fix this by moving the 'out' label below the hardware register cleanup.
If i801_check_pre() fails, we safely bypass the iowrite8() and only
release the software locks (pm_runtime and mutex), strictly adhering to
the rule of not releasing resources that were never acquired.
References
Impacted products
{
"containers": {
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"product": "Linux",
"programFiles": [
"drivers/i2c/busses/i2c-i801.c"
],
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"product": "Linux",
"programFiles": [
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.3"
},
{
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"status": "unaffected",
"version": "0",
"versionType": "semver"
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{
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"status": "unaffected",
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{
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"status": "unaffected",
"version": "6.18.39",
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{
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"status": "unaffected",
"version": "7.1.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
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"vulnerable": true
},
{
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{
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{
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ni2c: i801: fix hardware state machine corruption in error path\n\nA severe livelock and subsequent Hung Task panic were observed in the\ni2c-i801 driver during concurrent Fuzzing. The crash is caused by an\nunconditional hardware register cleanup in the error handling path of\ni801_access().\n\nWhen i801_check_pre() fails (e.g., returning -EBUSY because the SMBus\ncontroller is actively used by BIOS/ACPI), the kernel does not actually\nacquire the hardware ownership. However, the code jumps to the \u0027out\u0027\nlabel and executes:\n\n iowrite8(SMBHSTSTS_INUSE_STS | STATUS_FLAGS, SMBHSTSTS(priv));\n\nThis forcefully clears the INUSE_STS lock and resets the hardware status\nflags without owning the controller. Doing so interrupts ongoing BIOS/ACPI\ntransactions and totally corrupts the SMBus hardware state machine.\n\nConsequently, all subsequent i801_access() calls fail at the pre-check\nstage, triggering an endless stream of \"SMBus is busy, can\u0027t use it!\"\nerror logs. Over a slow serial console, this printk flood monopolizes\nthe CPU (Console Livelock), starving other processes trying to acquire\nthe mmap_lock down_read semaphore, ultimately triggering the hung task\nwatchdog.\n\nFix this by moving the \u0027out\u0027 label below the hardware register cleanup.\nIf i801_check_pre() fails, we safely bypass the iowrite8() and only\nrelease the software locks (pm_runtime and mutex), strictly adhering to\nthe rule of not releasing resources that were never acquired."
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T04:51:51.900Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/2ef69871b313aa0f02182795f5e0f5aa455f203c"
},
{
"url": "https://git.kernel.org/stable/c/ef5a347532932f58748dad485c15039f5168c377"
},
{
"url": "https://git.kernel.org/stable/c/bb5133a7d5f3fe5c387770e25f2e00e682ce11ed"
},
{
"url": "https://git.kernel.org/stable/c/00904687b9c5527d569d9a1ca72119823e735a61"
},
{
"url": "https://git.kernel.org/stable/c/10dd1a736d557e310a77117832874729a0175d57"
}
],
"title": "i2c: i801: fix hardware state machine corruption in error path",
"x_generator": {
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}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-64205",
"datePublished": "2026-07-20T16:27:53.310Z",
"dateReserved": "2026-07-19T15:36:31.769Z",
"dateUpdated": "2026-08-17T04:51:51.900Z",
"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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