{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-63893", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T07:54:57.019Z", "datePublished": "2026-07-19T14:55:04.288Z", "dateUpdated": "2026-08-05T12:36:59.715Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:36:59.715Z" }, "descriptions": [ { "lang": "en", "value": "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 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." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H", "baseScore": 8.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:A - A malicious Thunderbolt XDomain peer (adjacent host, dock, or in-line device on a direct Thunderbolt/USB4 link) delivers crafted PROPERTIES_RESPONSE data that the victim kernel parses during automatic XDomain discovery.\nAC:L - The peer fully controls property entry value/length fields and can reliably craft the u32 wrap (e.g. value=0xffffff00, length=0x100) without races or special memory layout.\nPR:N - Exploitation requires no privileges on the victim system; the attacker only needs to be the connected XDomain peer responding to the kernel-initiated property exchange, with no authentication on that control-plane path.\nUI:N - Once a Thunderbolt XDomain link exists, property fetching and parsing run automatically in the kernel handshake state machine without any additional victim user action at exploitation time.\nS:U - Impact is confined to the victim kernel/userspace boundary (kernel heap disclosure to local sysfs and possible kernel crash); it does not cross VM, IOMMU, or sandbox security boundaries.\nC:H - Integer-wrap bypass enables an out-of-bounds kernel memory read of up to entry->length dwords, which for deviceid/vendorid TEXT properties is copied into world-readable sysfs attributes, disclosing kernel heap contents.\nI:N - The bug is an out-of-bounds read via parse_dwdata(); destination buffers are properly sized kcalloc allocations, so there is no out-of-bounds write or integrity modification of victim kernel structures.\nA:H - Reading from block+0xffffff00 dwords (~4 GB past the allocation) will access unmapped kernel addresses, causing a kernel fault/oops/panic in addition to any information disclosure." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/thunderbolt/property.c" ], "versions": [ { "version": "cdae7c07e3e3509eaabc18c1640a55dc5b99c179", "lessThan": "6a63623621639acbb39bc2d9fb09559681716695", "status": "affected", "versionType": "git" }, { "version": "cdae7c07e3e3509eaabc18c1640a55dc5b99c179", "lessThan": "e8a0b0a93a6ef958e70b1dd4930beb6dc0026b36", "status": "affected", "versionType": "git" }, { "version": "cdae7c07e3e3509eaabc18c1640a55dc5b99c179", "lessThan": "9fee50c4e1e42f6d3cbe30df584f9f648f626071", "status": "affected", "versionType": "git" }, { "version": "cdae7c07e3e3509eaabc18c1640a55dc5b99c179", "lessThan": "8d4a758b407ab3de3be86d1ceadfa35d717d30c7", "status": "affected", "versionType": "git" }, { "version": "cdae7c07e3e3509eaabc18c1640a55dc5b99c179", "lessThan": "5c06a3043ad944f087bb2ae0aae28d820bb9f460", "status": "affected", "versionType": "git" }, { "version": "cdae7c07e3e3509eaabc18c1640a55dc5b99c179", "lessThan": "31b98e503ecca8077e5247253dd5425ab84bc96d", "status": "affected", "versionType": "git" }, { "version": "cdae7c07e3e3509eaabc18c1640a55dc5b99c179", "lessThan": "a47784aee77f33f786dc5d7375db821bdae68792", "status": "affected", "versionType": "git" }, { "version": "cdae7c07e3e3509eaabc18c1640a55dc5b99c179", "lessThan": "01deda0152066c6c955f0619114ea6afa070aaec", "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/thunderbolt/property.c" ], "versions": [ { "version": "4.15", "status": "affected" }, { "version": "0", "lessThan": "4.15", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.259", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.210", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.176", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.143", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.93", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.35", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.12", "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": "4.15", "versionEndExcluding": "5.10.259" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "5.15.210" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.1.176" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.6.143" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.12.93" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "6.18.35" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "7.0.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "7.1" } ] } ] } ], "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" } ], "title": "thunderbolt: property: Reject u32 wrap in tb_property_entry_valid()", "x_generator": { "engine": "bippy-1.2.0" } } } }