CVE-2026-64191

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-64191", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T07:54:57.040Z", "datePublished": "2026-07-20T16:27:51.120Z", "dateUpdated": "2026-10-19T20:28:15.069Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:39:59.861Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ni2c: stub: Reject I2C block transfers with invalid length\n\nThe I2C_SMBUS_I2C_BLOCK_DATA case in stub_xfer() uses data->block[0]\nas the transfer length. The existing check only clamps it to avoid\noverrunning the chip->words[256] register array, but does not validate\nit against I2C_SMBUS_BLOCK_MAX (32), which is the limit of the union\ni2c_smbus_data.block buffer (34 bytes total). The driver is a\ndevelopment/test tool (CONFIG_I2C_STUB=m, not built by default)\nthat must be loaded with a chip_addr= parameter.\n\nA local user with access to /dev/i2c-* can issue an I2C_SMBUS ioctl\nwith I2C_SMBUS_I2C_BLOCK_DATA and data->block[0] > 32, causing\nstub_xfer() to read or write past the end of the union\ni2c_smbus_data.block buffer:\n\n BUG: KASAN: stack-out-of-bounds in stub_xfer (drivers/i2c/i2c-stub.c:223)\n Read of size 1 at addr ffff88800abcfd92 by task exploit/81\n Call Trace:\n <TASK>\n stub_xfer (drivers/i2c/i2c-stub.c:223)\n __i2c_smbus_xfer (drivers/i2c/i2c-core-smbus.c:593)\n i2c_smbus_xfer (drivers/i2c/i2c-core-smbus.c:536)\n i2cdev_ioctl_smbus (drivers/i2c/i2c-dev.c:391)\n i2cdev_ioctl (drivers/i2c/i2c-dev.c:478)\n __x64_sys_ioctl (fs/ioctl.c:583)\n do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\n </TASK>\n\nThe bug exists because i2c-stub implements .smbus_xfer directly,\nbypassing the I2C_SMBUS_BLOCK_MAX validation in\ni2c_smbus_xfer_emulated(). The I2C_SMBUS_BLOCK_DATA case in the same\nfunction correctly validates against I2C_SMBUS_BLOCK_MAX, but the\nI2C_SMBUS_I2C_BLOCK_DATA case does not.\n\nFix by rejecting transfers with data->block[0] == 0 or\ndata->block[0] > I2C_SMBUS_BLOCK_MAX with -EINVAL, consistent with\nboth the I2C_SMBUS_BLOCK_DATA case in the same function and the\nI2C_SMBUS_I2C_BLOCK_DATA validation in i2c_smbus_xfer_emulated()."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - The vulnerable path is reached by a local process issuing I2C_SMBUS ioctls on an i2c-stub /dev/i2c-* character device; it is neither remotely nor physically reachable.\nAC:L - Once i2c-stub is loaded, the attacker controls the address, direction, length, and register contents, making the corruption deterministic without a race. The non-default module configuration defines the vulnerable deployment rather than complicating exploitation within it.\nPR:L - The attacker needs unprivileged local access to the applicable /dev/i2c-* node, but no capability or namespace-specific administrative privilege is checked anywhere along the ioctl path.\nUI:N - After the vulnerable adapter is configured, exploitation requires only attacker-issued ioctls and no action by another user.\nS:U - The corruption occurs within the host kernel and represents conventional local privilege escalation, without crossing a separate virtualization or hardware security authority.\nC:H - An oversized block write reads up to 222 bytes beyond the 34-byte stack union and persists those bytes in attacker-readable stub registers, enabling substantial kernel-stack disclosure.\nI:H - An oversized block read writes up to 222 attacker-chosen bytes beyond the stack union because the attacker can prepopulate the stub registers, enabling control-data corruption and potential kernel code execution.\nA:H - The controlled stack overwrite can corrupt stack canaries, return state, or other control data, causing a repeatable kernel oops or panic even when code execution is unsuccessful."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/i2c/i2c-stub.c"], "versions": [{"version": "4710317891e4824ce1510a6b5066abbd3e917750", "lessThan": "7e9072dbd5f2f17934751873450d2c22080ead80", "status": "affected", "versionType": "git"}, {"version": "4710317891e4824ce1510a6b5066abbd3e917750", "lessThan": "21e87f336ac6303fed54a69b1d0d79a23b25c8d0", "status": "affected", "versionType": "git"}, {"version": "4710317891e4824ce1510a6b5066abbd3e917750", "lessThan": "3fd225f3e4cd67ec8ddab1afed9da03c7c43537c", "status": "affected", "versionType": "git"}, {"version": "4710317891e4824ce1510a6b5066abbd3e917750", "lessThan": "1c4ffe6b4f04365485ed58d64c9bb86b46fc9037", "status": "affected", "versionType": "git"}, {"version": "4710317891e4824ce1510a6b5066abbd3e917750", "lessThan": "4bd8635f28c135a08aac6badcd7d9b5cdb34335f", "status": "affected", "versionType": "git"}, {"version": "4710317891e4824ce1510a6b5066abbd3e917750", "lessThan": "5f4d2bd028ebb6e4c09a9d64842546022321d4a7", "status": "affected", "versionType": "git"}, {"version": "4710317891e4824ce1510a6b5066abbd3e917750", "lessThan": "0526931b16e5a118d367b7bfce7d797e63f7ac69", "status": "affected", "versionType": "git"}, {"version": "4710317891e4824ce1510a6b5066abbd3e917750", "lessThan": "6036b5067a8199ba7a2dc7b377d4b9dd276d5f9e", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/i2c/i2c-stub.c"], "versions": [{"version": "2.6.33", "status": "affected"}, {"version": "0", "lessThan": "2.6.33", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.260", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.211", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.177", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.144", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.95", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.37", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0.14", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "5.10.260"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "5.15.211"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "6.1.177"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "6.6.144"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "6.12.95"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "6.18.37"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "7.0.14"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.33", "versionEndExcluding": "7.1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/7e9072dbd5f2f17934751873450d2c22080ead80"}, {"url": "https://git.kernel.org/stable/c/21e87f336ac6303fed54a69b1d0d79a23b25c8d0"}, {"url": "https://git.kernel.org/stable/c/3fd225f3e4cd67ec8ddab1afed9da03c7c43537c"}, {"url": "https://git.kernel.org/stable/c/1c4ffe6b4f04365485ed58d64c9bb86b46fc9037"}, {"url": "https://git.kernel.org/stable/c/4bd8635f28c135a08aac6badcd7d9b5cdb34335f"}, {"url": "https://git.kernel.org/stable/c/5f4d2bd028ebb6e4c09a9d64842546022321d4a7"}, {"url": "https://git.kernel.org/stable/c/0526931b16e5a118d367b7bfce7d797e63f7ac69"}, {"url": "https://git.kernel.org/stable/c/6036b5067a8199ba7a2dc7b377d4b9dd276d5f9e"}], "title": "i2c: stub: Reject I2C block transfers with invalid length", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-64191", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T15:37:24.187565Z"}}}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-787", "description": "CWE-787 Out-of-bounds Write"}]}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-19T20:28:15.069Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-64191", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T15:37:24.187565Z"}}}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-787", "description": "CWE-787 Out-of-bounds Write"}]}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T15:37:25.476Z"}}], "cna": {"title": "i2c: stub: Reject I2C block transfers with invalid length", "metrics": [{"cvssV3_1": {"version": "3.1", "baseScore": 7.8, "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}, "scenarios": [{"lang": "en", "value": "AV:L - The vulnerable path is reached by a local process issuing I2C_SMBUS ioctls on an i2c-stub /dev/i2c-* character device; it is neither remotely nor physically reachable.\nAC:L - Once i2c-stub is loaded, the attacker controls the address, direction, length, and register contents, making the corruption deterministic without a race. The non-default module configuration defines the vulnerable deployment rather than complicating exploitation within it.\nPR:L - The attacker needs unprivileged local access to the applicable /dev/i2c-* node, but no capability or namespace-specific administrative privilege is checked anywhere along the ioctl path.\nUI:N - After the vulnerable adapter is configured, exploitation requires only attacker-issued ioctls and no action by another user.\nS:U - The corruption occurs within the host kernel and represents conventional local privilege escalation, without crossing a separate virtualization or hardware security authority.\nC:H - An oversized block write reads up to 222 bytes beyond the 34-byte stack union and persists those bytes in attacker-readable stub registers, enabling substantial kernel-stack disclosure.\nI:H - An oversized block read writes up to 222 attacker-chosen bytes beyond the stack union because the attacker can prepopulate the stub registers, enabling control-data corruption and potential kernel code execution.\nA:H - The controlled stack overwrite can corrupt stack canaries, return state, or other control data, causing a repeatable kernel oops or panic even when code execution is unsuccessful."}]}], "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "4710317891e4824ce1510a6b5066abbd3e917750", "lessThan": "7e9072dbd5f2f17934751873450d2c22080ead80", "versionType": "git"}, {"status": "affected", "version": "4710317891e4824ce1510a6b5066abbd3e917750", "lessThan": "21e87f336ac6303fed54a69b1d0d79a23b25c8d0", "versionType": "git"}, {"status": "affected", "version": "4710317891e4824ce1510a6b5066abbd3e917750", "lessThan": "3fd225f3e4cd67ec8ddab1afed9da03c7c43537c", "versionType": "git"}, {"status": "affected", "version": "4710317891e4824ce1510a6b5066abbd3e917750", "lessThan": "1c4ffe6b4f04365485ed58d64c9bb86b46fc9037", "versionType": "git"}, {"status": "affected", "version": "4710317891e4824ce1510a6b5066abbd3e917750", "lessThan": "4bd8635f28c135a08aac6badcd7d9b5cdb34335f", "versionType": "git"}, {"status": "affected", "version": "4710317891e4824ce1510a6b5066abbd3e917750", "lessThan": "5f4d2bd028ebb6e4c09a9d64842546022321d4a7", "versionType": "git"}, {"status": "affected", "version": "4710317891e4824ce1510a6b5066abbd3e917750", "lessThan": "0526931b16e5a118d367b7bfce7d797e63f7ac69", "versionType": "git"}, {"status": "affected", "version": "4710317891e4824ce1510a6b5066abbd3e917750", "lessThan": "6036b5067a8199ba7a2dc7b377d4b9dd276d5f9e", "versionType": "git"}], "programFiles": ["drivers/i2c/i2c-stub.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "2.6.33"}, {"status": "unaffected", "version": "0", "lessThan": "2.6.33", "versionType": "semver"}, {"status": "unaffected", "version": "5.10.260", "versionType": "semver", "lessThanOrEqual": "5.10.*"}, {"status": "unaffected", "version": "5.15.211", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "6.1.177", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.144", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.95", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.18.37", "versionType": "semver", "lessThanOrEqual": "6.18.*"}, {"status": "unaffected", "version": "7.0.14", "versionType": "semver", "lessThanOrEqual": "7.0.*"}, {"status": "unaffected", "version": "7.1", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["drivers/i2c/i2c-stub.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/7e9072dbd5f2f17934751873450d2c22080ead80"}, {"url": "https://git.kernel.org/stable/c/21e87f336ac6303fed54a69b1d0d79a23b25c8d0"}, {"url": "https://git.kernel.org/stable/c/3fd225f3e4cd67ec8ddab1afed9da03c7c43537c"}, {"url": "https://git.kernel.org/stable/c/1c4ffe6b4f04365485ed58d64c9bb86b46fc9037"}, {"url": "https://git.kernel.org/stable/c/4bd8635f28c135a08aac6badcd7d9b5cdb34335f"}, {"url": "https://git.kernel.org/stable/c/5f4d2bd028ebb6e4c09a9d64842546022321d4a7"}, {"url": "https://git.kernel.org/stable/c/0526931b16e5a118d367b7bfce7d797e63f7ac69"}, {"url": "https://git.kernel.org/stable/c/6036b5067a8199ba7a2dc7b377d4b9dd276d5f9e"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ni2c: stub: Reject I2C block transfers with invalid length\n\nThe I2C_SMBUS_I2C_BLOCK_DATA case in stub_xfer() uses data->block[0]\nas the transfer length. The existing check only clamps it to avoid\noverrunning the chip->words[256] register array, but does not validate\nit against I2C_SMBUS_BLOCK_MAX (32), which is the limit of the union\ni2c_smbus_data.block buffer (34 bytes total). The driver is a\ndevelopment/test tool (CONFIG_I2C_STUB=m, not built by default)\nthat must be loaded with a chip_addr= parameter.\n\nA local user with access to /dev/i2c-* can issue an I2C_SMBUS ioctl\nwith I2C_SMBUS_I2C_BLOCK_DATA and data->block[0] > 32, causing\nstub_xfer() to read or write past the end of the union\ni2c_smbus_data.block buffer:\n\n BUG: KASAN: stack-out-of-bounds in stub_xfer (drivers/i2c/i2c-stub.c:223)\n Read of size 1 at addr ffff88800abcfd92 by task exploit/81\n Call Trace:\n <TASK>\n stub_xfer (drivers/i2c/i2c-stub.c:223)\n __i2c_smbus_xfer (drivers/i2c/i2c-core-smbus.c:593)\n i2c_smbus_xfer (drivers/i2c/i2c-core-smbus.c:536)\n i2cdev_ioctl_smbus (drivers/i2c/i2c-dev.c:391)\n i2cdev_ioctl (drivers/i2c/i2c-dev.c:478)\n __x64_sys_ioctl (fs/ioctl.c:583)\n do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\n </TASK>\n\nThe bug exists because i2c-stub implements .smbus_xfer directly,\nbypassing the I2C_SMBUS_BLOCK_MAX validation in\ni2c_smbus_xfer_emulated(). The I2C_SMBUS_BLOCK_DATA case in the same\nfunction correctly validates against I2C_SMBUS_BLOCK_MAX, but the\nI2C_SMBUS_I2C_BLOCK_DATA case does not.\n\nFix by rejecting transfers with data->block[0] == 0 or\ndata->block[0] > I2C_SMBUS_BLOCK_MAX with -EINVAL, consistent with\nboth the I2C_SMBUS_BLOCK_DATA case in the same function and the\nI2C_SMBUS_I2C_BLOCK_DATA validation in i2c_smbus_xfer_emulated()."}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.10.260", "versionStartIncluding": "2.6.33"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.15.211", "versionStartIncluding": "2.6.33"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.1.177", "versionStartIncluding": "2.6.33"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.6.144", "versionStartIncluding": "2.6.33"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.12.95", "versionStartIncluding": "2.6.33"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.18.37", "versionStartIncluding": "2.6.33"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.0.14", "versionStartIncluding": "2.6.33"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.1", "versionStartIncluding": "2.6.33"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:39:59.861Z"}}}, "cveMetadata": {"cveId": "CVE-2026-64191", "state": "PUBLISHED", "dateUpdated": "2026-10-19T20:28:15.069Z", "dateReserved": "2026-07-19T07:54:57.040Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2026-07-20T16:27:51.120Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

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The existing check only clamps it to avoid\noverrunning the chip->words[256] register array, but does not validate\nit against I2C_SMBUS_BLOCK_MAX (32), which is the limit of the union\ni2c_smbus_data.block buffer (34 bytes total). The driver is a\ndevelopment/test tool (CONFIG_I2C_STUB=m, not built by default)\nthat must be loaded with a chip_addr= parameter.\n\nA local user with access to /dev/i2c-* can issue an I2C_SMBUS ioctl\nwith I2C_SMBUS_I2C_BLOCK_DATA and data->block[0] > 32, causing\nstub_xfer() to read or write past the end of the union\ni2c_smbus_data.block buffer:\n\n BUG: KASAN: stack-out-of-bounds in stub_xfer (drivers/i2c/i2c-stub.c:223)\n Read of size 1 at addr ffff88800abcfd92 by task exploit/81\n Call Trace:\n <TASK>\n stub_xfer (drivers/i2c/i2c-stub.c:223)\n __i2c_smbus_xfer (drivers/i2c/i2c-core-smbus.c:593)\n i2c_smbus_xfer (drivers/i2c/i2c-core-smbus.c:536)\n i2cdev_ioctl_smbus (drivers/i2c/i2c-dev.c:391)\n i2cdev_ioctl (drivers/i2c/i2c-dev.c:478)\n __x64_sys_ioctl (fs/ioctl.c:583)\n do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\n </TASK>\n\nThe bug exists because i2c-stub implements .smbus_xfer directly,\nbypassing the I2C_SMBUS_BLOCK_MAX validation in\ni2c_smbus_xfer_emulated(). The I2C_SMBUS_BLOCK_DATA case in the same\nfunction correctly validates against I2C_SMBUS_BLOCK_MAX, but the\nI2C_SMBUS_I2C_BLOCK_DATA case does not.\n\nFix by rejecting transfers with data->block[0] == 0 or\ndata->block[0] > I2C_SMBUS_BLOCK_MAX with -EINVAL, consistent with\nboth the I2C_SMBUS_BLOCK_DATA case in the same function and the\nI2C_SMBUS_I2C_BLOCK_DATA validation in i2c_smbus_xfer_emulated()."}], "id": "CVE-2026-64191", "lastModified": "2026-10-19T21:17:26.730", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-64191", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-10-16T15:37:24.187565Z", "version": "2.0.3"}}]}, "published": "2026-07-20T17:18:22.217", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/0526931b16e5a118d367b7bfce7d797e63f7ac69"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/1c4ffe6b4f04365485ed58d64c9bb86b46fc9037"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/21e87f336ac6303fed54a69b1d0d79a23b25c8d0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/3fd225f3e4cd67ec8ddab1afed9da03c7c43537c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/4bd8635f28c135a08aac6badcd7d9b5cdb34335f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/5f4d2bd028ebb6e4c09a9d64842546022321d4a7"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/6036b5067a8199ba7a2dc7b377d4b9dd276d5f9e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/7e9072dbd5f2f17934751873450d2c22080ead80"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-125"}], "source": "nvd@nist.gov", "type": "Primary"}, {"description": [{"lang": "en", "value": "CWE-787"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}

{"bugzilla": {"description": "kernel: i2c: stub: Reject I2C block transfers with invalid length", "id": "2502872", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2502872"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-787", "details": ["A flaw was found in the Linux kernel's `i2c-stub` driver. A local user with access to the `/dev/i2c-*` device can exploit this vulnerability by issuing an I2C System Management Bus (SMBus) input/output control (ioctl) command with a specially crafted block transfer length. This invalid length can cause the driver to read or write beyond the allocated buffer, leading to a stack-out-of-bounds error and a system crash, resulting in a Denial of Service (DoS)."], "name": "CVE-2026-64191", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-07-20T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-64191\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-64191\nhttps://lore.kernel.org/linux-cve-announce/2026072052-CVE-2026-64191-42fe@gregkh/T"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4710317891e4824ce1510a6b5066abbd3e917750,7e9072dbd5f2f17934751873450d2c22080ead80)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4710317891e4824ce1510a6b5066abbd3e917750,21e87f336ac6303fed54a69b1d0d79a23b25c8d0)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4710317891e4824ce1510a6b5066abbd3e917750,3fd225f3e4cd67ec8ddab1afed9da03c7c43537c)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4710317891e4824ce1510a6b5066abbd3e917750,1c4ffe6b4f04365485ed58d64c9bb86b46fc9037)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4710317891e4824ce1510a6b5066abbd3e917750,4bd8635f28c135a08aac6badcd7d9b5cdb34335f)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4710317891e4824ce1510a6b5066abbd3e917750,5f4d2bd028ebb6e4c09a9d64842546022321d4a7)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4710317891e4824ce1510a6b5066abbd3e917750,0526931b16e5a118d367b7bfce7d797e63f7ac69)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4710317891e4824ce1510a6b5066abbd3e917750,6036b5067a8199ba7a2dc7b377d4b9dd276d5f9e)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "2.6.33"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,2.6.33)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[5.10.260,5.10.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[5.15.211,5.15.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.1.177,6.1.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.144,6.6.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.95,6.12.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.37,6.18.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.0.14,7.0.*]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-07-21T01:30:17.675143+00:00", "updated": "2026-08-13T12:00:05.146652+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-125", "CWE-787"]}