{"id":"CVE-2026-64205","state":"PUBLISHED","title":"i2c: i801: fix hardware state machine corruption in error path","description":"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 'out'\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't 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 'out' 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.","publishedAt":"2026-07-20T16:27:53.310Z","updatedAt":"2026-08-17T04:51:51.900Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1f760b87e54cf56a25ab68f8dc625e339f6e46d5","status":"affected","lessThan":"2ef69871b313aa0f02182795f5e0f5aa455f203c","versionType":"git"},{"version":"1f760b87e54cf56a25ab68f8dc625e339f6e46d5","status":"affected","lessThan":"ef5a347532932f58748dad485c15039f5168c377","versionType":"git"},{"version":"1f760b87e54cf56a25ab68f8dc625e339f6e46d5","status":"affected","lessThan":"bb5133a7d5f3fe5c387770e25f2e00e682ce11ed","versionType":"git"},{"version":"1f760b87e54cf56a25ab68f8dc625e339f6e46d5","status":"affected","lessThan":"00904687b9c5527d569d9a1ca72119823e735a61","versionType":"git"},{"version":"1f760b87e54cf56a25ab68f8dc625e339f6e46d5","status":"affected","lessThan":"10dd1a736d557e310a77117832874729a0175d57","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/i2c/busses/i2c-i801.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.3","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.3","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.39","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.4","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/i2c/busses/i2c-i801.c"]}],"references":["https://git.kernel.org/stable/c/2ef69871b313aa0f02182795f5e0f5aa455f203c","https://git.kernel.org/stable/c/ef5a347532932f58748dad485c15039f5168c377","https://git.kernel.org/stable/c/bb5133a7d5f3fe5c387770e25f2e00e682ce11ed","https://git.kernel.org/stable/c/00904687b9c5527d569d9a1ca72119823e735a61","https://git.kernel.org/stable/c/10dd1a736d557e310a77117832874729a0175d57"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64205.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64205","state":"PUBLISHED","datePublished":"2026-07-20T16:27:53.310Z","dateUpdated":"2026-08-17T04:51:51.900Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T15:36:31.769Z"},"containers":{"cna":{"title":"i2c: i801: fix hardware state machine corruption in error path","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 'out'\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't 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 'out' 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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1f760b87e54cf56a25ab68f8dc625e339f6e46d5","status":"affected","lessThan":"2ef69871b313aa0f02182795f5e0f5aa455f203c","versionType":"git"},{"version":"1f760b87e54cf56a25ab68f8dc625e339f6e46d5","status":"affected","lessThan":"ef5a347532932f58748dad485c15039f5168c377","versionType":"git"},{"version":"1f760b87e54cf56a25ab68f8dc625e339f6e46d5","status":"affected","lessThan":"bb5133a7d5f3fe5c387770e25f2e00e682ce11ed","versionType":"git"},{"version":"1f760b87e54cf56a25ab68f8dc625e339f6e46d5","status":"affected","lessThan":"00904687b9c5527d569d9a1ca72119823e735a61","versionType":"git"},{"version":"1f760b87e54cf56a25ab68f8dc625e339f6e46d5","status":"affected","lessThan":"10dd1a736d557e310a77117832874729a0175d57","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/i2c/busses/i2c-i801.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.3","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.3","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.39","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.4","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/i2c/busses/i2c-i801.c"]}],"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"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:51:51.900Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.3","versionEndExcluding":"6.6.148"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.3","versionEndExcluding":"6.12.101"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.3","versionEndExcluding":"6.18.39"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.3","versionEndExcluding":"7.1.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.3","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}