{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-64191", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-64191", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-07-20T16:27:51.120Z", "updatedAt": "2026-10-19T20:28:15.069Z", "importedAt": "2026-10-24T01:58:25.636Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "i2c: stub: Reject I2C block transfers with invalid length", "summary": "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 \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 \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().", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "4710317891e4824ce1510a6b5066abbd3e917750", "status": "affected", "versionType": "git", "lessThan": "7e9072dbd5f2f17934751873450d2c22080ead80" }, { "version": "4710317891e4824ce1510a6b5066abbd3e917750", "status": "affected", "versionType": "git", "lessThan": "21e87f336ac6303fed54a69b1d0d79a23b25c8d0" }, { "version": "4710317891e4824ce1510a6b5066abbd3e917750", "status": "affected", "versionType": "git", "lessThan": "3fd225f3e4cd67ec8ddab1afed9da03c7c43537c" }, { "version": "4710317891e4824ce1510a6b5066abbd3e917750", "status": "affected", "versionType": "git", "lessThan": "1c4ffe6b4f04365485ed58d64c9bb86b46fc9037" }, { "version": "4710317891e4824ce1510a6b5066abbd3e917750", "status": "affected", "versionType": "git", "lessThan": "4bd8635f28c135a08aac6badcd7d9b5cdb34335f" }, { "version": "4710317891e4824ce1510a6b5066abbd3e917750", "status": "affected", "versionType": "git", "lessThan": "5f4d2bd028ebb6e4c09a9d64842546022321d4a7" }, { "version": "4710317891e4824ce1510a6b5066abbd3e917750", "status": "affected", "versionType": "git", "lessThan": "0526931b16e5a118d367b7bfce7d797e63f7ac69" }, { "version": "4710317891e4824ce1510a6b5066abbd3e917750", "status": "affected", "versionType": "git", "lessThan": "6036b5067a8199ba7a2dc7b377d4b9dd276d5f9e" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "2.6.33", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "2.6.33" }, { "version": "5.10.260", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.211", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.177", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.144", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.95", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.37", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.0.14", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.0.*" }, { "version": "7.1", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }