{"id":"CVE-2026-63893","title":"thunderbolt: property: Reject u32 wrap in tb_property_entry_valid()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nthunderbolt: property: Reject u32 wrap in tb_property_entry_valid()\n\nentry->value is u32 and entry->length is u16; the sum is performed in\nu32 and wraps.  A malicious X…","severity":"high","cvss":8.1,"cvssVector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= cdae7c07e3e3509eaabc18c1640a55dc5b99c179 < 6a63623621639acbb39bc2d9fb09559681716695","Linux >= cdae7c07e3e3509eaabc18c1640a55dc5b99c179 < e8a0b0a93a6ef958e70b1dd4930beb6dc0026b36","Linux >= cdae7c07e3e3509eaabc18c1640a55dc5b99c179 < 9fee50c4e1e42f6d3cbe30df584f9f648f626071","Linux >= cdae7c07e3e3509eaabc18c1640a55dc5b99c179 < 8d4a758b407ab3de3be86d1ceadfa35d717d30c7","Linux >= cdae7c07e3e3509eaabc18c1640a55dc5b99c179 < 5c06a3043ad944f087bb2ae0aae28d820bb9f460","Linux >= cdae7c07e3e3509eaabc18c1640a55dc5b99c179 < 31b98e503ecca8077e5247253dd5425ab84bc96d","Linux >= cdae7c07e3e3509eaabc18c1640a55dc5b99c179 < a47784aee77f33f786dc5d7375db821bdae68792","Linux >= cdae7c07e3e3509eaabc18c1640a55dc5b99c179 < 01deda0152066c6c955f0619114ea6afa070aaec","Linux 4.15"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-16T15:33:06.328646Z"},"published":"2026-07-19","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:42:10.643Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-63893","references":[{"url":"https://git.kernel.org/stable/c/6a63623621639acbb39bc2d9fb09559681716695"},{"url":"https://git.kernel.org/stable/c/e8a0b0a93a6ef958e70b1dd4930beb6dc0026b36"},{"url":"https://git.kernel.org/stable/c/9fee50c4e1e42f6d3cbe30df584f9f648f626071"},{"url":"https://git.kernel.org/stable/c/8d4a758b407ab3de3be86d1ceadfa35d717d30c7"},{"url":"https://git.kernel.org/stable/c/5c06a3043ad944f087bb2ae0aae28d820bb9f460"},{"url":"https://git.kernel.org/stable/c/31b98e503ecca8077e5247253dd5425ab84bc96d"},{"url":"https://git.kernel.org/stable/c/a47784aee77f33f786dc5d7375db821bdae68792"},{"url":"https://git.kernel.org/stable/c/01deda0152066c6c955f0619114ea6afa070aaec"}],"tags":["cve.org"],"epss":0.00386,"epssPercentile":0.31074,"ingestedAt":"2026-10-16T17:24:46.773Z","slug":"CVE-2026-63893","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nthunderbolt: property: Reject u32 wrap in tb_property_entry_valid()\n\nentry->value is u32 and entry->length is u16; the sum is performed in\nu32 and wraps.  A malicious XDomain peer can pick\nvalue = 0xffffff00, length = 0x100 so the sum 0x100000000 wraps to 0\nand passes the > block_len check.  tb_property_parse() then passes\nentry->value to parse_dwdata() as a dword offset into the property\nblock, reading attacker-directed memory far past the allocation.\n\nFor TEXT-typed entries with the \"deviceid\" or \"vendorid\" keys this\nlands in xd->device_name / xd->vendor_name and is readable back via\nthe per-XDomain device_name / vendor_name sysfs attributes; the leak\nis NUL-bounded (kstrdup() stops at the first zero byte) and\nuntargeted (the attacker picks a delta, not an absolute address).\nDATA-typed entries are parsed into property->value.data but not\ngenerically surfaced to userspace.\n\nUse check_add_overflow() so a wrapped sum is rejected.\n\n## Affected\n\n- `Linux >= cdae7c07e3e3509eaabc18c1640a55dc5b99c179 < 6a63623621639acbb39bc2d9fb09559681716695`\n- `Linux >= cdae7c07e3e3509eaabc18c1640a55dc5b99c179 < e8a0b0a93a6ef958e70b1dd4930beb6dc0026b36`\n- `Linux >= cdae7c07e3e3509eaabc18c1640a55dc5b99c179 < 9fee50c4e1e42f6d3cbe30df584f9f648f626071`\n- `Linux >= cdae7c07e3e3509eaabc18c1640a55dc5b99c179 < 8d4a758b407ab3de3be86d1ceadfa35d717d30c7`\n- `Linux >= cdae7c07e3e3509eaabc18c1640a55dc5b99c179 < 5c06a3043ad944f087bb2ae0aae28d820bb9f460`\n- `Linux >= cdae7c07e3e3509eaabc18c1640a55dc5b99c179 < 31b98e503ecca8077e5247253dd5425ab84bc96d`\n- `Linux >= cdae7c07e3e3509eaabc18c1640a55dc5b99c179 < a47784aee77f33f786dc5d7375db821bdae68792`\n- `Linux >= cdae7c07e3e3509eaabc18c1640a55dc5b99c179 < 01deda0152066c6c955f0619114ea6afa070aaec`\n- `Linux 4.15`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":44.6,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}