{"api_version":"1","generated_at":"2026-07-24T17:43:41+00:00","cve":"CVE-2026-63892","urls":{"html":"https://cve.report/CVE-2026-63892","api":"https://cve.report/api/cve/CVE-2026-63892.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-63892","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-63892"},"summary":{"title":"thunderbolt: property: Reject dir_len < 4 to prevent size_t underflow","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nthunderbolt: property: Reject dir_len < 4 to prevent size_t underflow\n\nOn the non-root path, __tb_property_parse_dir() takes dir_len from\nentry->length (u16 widened to size_t).  Two distinct OOB conditions\nfollow when entry->length < 4:\n\n1. The non-root path begins with kmemdup(&block[dir_offset],\n   sizeof(*dir->uuid), ...) which always reads 4 dwords from\n   dir_offset.  tb_property_entry_valid() only enforces\n   dir_offset + entry->length <= block_len, so a crafted entry\n   with dir_offset close to the end of the property block and\n   entry->length in 0..3 passes that gate but lets the UUID copy\n   run off the block (e.g. dir_offset = 497, dir_len = 3 in a\n   500-dword block reads block[497..501]).\n\n2. After the kmemdup, content_len = dir_len - 4 underflows size_t\n   to ~SIZE_MAX, nentries becomes SIZE_MAX / 4, and the entry\n   walk runs OOB on each iteration until an entry fails\n   validation or the kernel oopses on an unmapped page.\n\nReject dir_len < 4 on the non-root path *before* the UUID kmemdup,\nwhich closes both holes.\n\nAlso move INIT_LIST_HEAD(&dir->properties) up to immediately after\nthe dir allocation so the new error-return path (and the existing\nuuid-alloc failure path) calling tb_property_free_dir() sees a\nwalkable list rather than the zero-initialized NULL next/prev that\nlist_for_each_entry_safe() would oops on.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-19 16:17:06","updated_at":"2026-07-19 16:17:06"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/37abc4504fa19d8f9f1e87792e8a2b8fdb308e40","name":"https://git.kernel.org/stable/c/37abc4504fa19d8f9f1e87792e8a2b8fdb308e40","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e2d4d51cf5785815fa4e91e0c019e3eb2506a84c","name":"https://git.kernel.org/stable/c/e2d4d51cf5785815fa4e91e0c019e3eb2506a84c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/5506c825f14d810f0690b1f4367cb7249ebb387a","name":"https://git.kernel.org/stable/c/5506c825f14d810f0690b1f4367cb7249ebb387a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/de618299190b418291609e6921557253bd417e25","name":"https://git.kernel.org/stable/c/de618299190b418291609e6921557253bd417e25","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/3bec49ca55e08fb085cc4318f24b1b37eaab28cb","name":"https://git.kernel.org/stable/c/3bec49ca55e08fb085cc4318f24b1b37eaab28cb","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d548179adcc87e1bc66b17e00352a1f536e76065","name":"https://git.kernel.org/stable/c/d548179adcc87e1bc66b17e00352a1f536e76065","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/542a13890b742099c461d70920e97b14e568f6ec","name":"https://git.kernel.org/stable/c/542a13890b742099c461d70920e97b14e568f6ec","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/de21b59c29e31c5108ddc04210631bbfab81b997","name":"https://git.kernel.org/stable/c/de21b59c29e31c5108ddc04210631bbfab81b997","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-63892","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63892","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cdae7c07e3e3509eaabc18c1640a55dc5b99c179 37abc4504fa19d8f9f1e87792e8a2b8fdb308e40 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cdae7c07e3e3509eaabc18c1640a55dc5b99c179 e2d4d51cf5785815fa4e91e0c019e3eb2506a84c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cdae7c07e3e3509eaabc18c1640a55dc5b99c179 de618299190b418291609e6921557253bd417e25 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cdae7c07e3e3509eaabc18c1640a55dc5b99c179 5506c825f14d810f0690b1f4367cb7249ebb387a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.210 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.176 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.143 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.93 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.35 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.12 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"63892","cve":"CVE-2026-63892","epss":"0.002200000","percentile":"0.125290000","score_date":"2026-07-20","updated_at":"2026-07-21 00:13:14"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/thunderbolt/property.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"37abc4504fa19d8f9f1e87792e8a2b8fdb308e40","status":"affected","version":"cdae7c07e3e3509eaabc18c1640a55dc5b99c179","versionType":"git"},{"lessThan":"e2d4d51cf5785815fa4e91e0c019e3eb2506a84c","status":"affected","version":"cdae7c07e3e3509eaabc18c1640a55dc5b99c179","versionType":"git"},{"lessThan":"de618299190b418291609e6921557253bd417e25","status":"affected","version":"cdae7c07e3e3509eaabc18c1640a55dc5b99c179","versionType":"git"},{"lessThan":"5506c825f14d810f0690b1f4367cb7249ebb387a","status":"affected","version":"cdae7c07e3e3509eaabc18c1640a55dc5b99c179","versionType":"git"},{"lessThan":"542a13890b742099c461d70920e97b14e568f6ec","status":"affected","version":"cdae7c07e3e3509eaabc18c1640a55dc5b99c179","versionType":"git"},{"lessThan":"d548179adcc87e1bc66b17e00352a1f536e76065","status":"affected","version":"cdae7c07e3e3509eaabc18c1640a55dc5b99c179","versionType":"git"},{"lessThan":"3bec49ca55e08fb085cc4318f24b1b37eaab28cb","status":"affected","version":"cdae7c07e3e3509eaabc18c1640a55dc5b99c179","versionType":"git"},{"lessThan":"de21b59c29e31c5108ddc04210631bbfab81b997","status":"affected","version":"cdae7c07e3e3509eaabc18c1640a55dc5b99c179","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/thunderbolt/property.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"4.15"},{"lessThan":"4.15","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.259","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.210","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.176","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.143","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.93","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.35","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.12","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.259","versionStartIncluding":"4.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.210","versionStartIncluding":"4.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.176","versionStartIncluding":"4.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.143","versionStartIncluding":"4.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.93","versionStartIncluding":"4.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.35","versionStartIncluding":"4.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.12","versionStartIncluding":"4.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1","versionStartIncluding":"4.15","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nthunderbolt: property: Reject dir_len < 4 to prevent size_t underflow\n\nOn the non-root path, __tb_property_parse_dir() takes dir_len from\nentry->length (u16 widened to size_t).  Two distinct OOB conditions\nfollow when entry->length < 4:\n\n1. The non-root path begins with kmemdup(&block[dir_offset],\n   sizeof(*dir->uuid), ...) which always reads 4 dwords from\n   dir_offset.  tb_property_entry_valid() only enforces\n   dir_offset + entry->length <= block_len, so a crafted entry\n   with dir_offset close to the end of the property block and\n   entry->length in 0..3 passes that gate but lets the UUID copy\n   run off the block (e.g. dir_offset = 497, dir_len = 3 in a\n   500-dword block reads block[497..501]).\n\n2. After the kmemdup, content_len = dir_len - 4 underflows size_t\n   to ~SIZE_MAX, nentries becomes SIZE_MAX / 4, and the entry\n   walk runs OOB on each iteration until an entry fails\n   validation or the kernel oopses on an unmapped page.\n\nReject dir_len < 4 on the non-root path *before* the UUID kmemdup,\nwhich closes both holes.\n\nAlso move INIT_LIST_HEAD(&dir->properties) up to immediately after\nthe dir allocation so the new error-return path (and the existing\nuuid-alloc failure path) calling tb_property_free_dir() sees a\nwalkable list rather than the zero-initialized NULL next/prev that\nlist_for_each_entry_safe() would oops on."}],"providerMetadata":{"dateUpdated":"2026-07-19T14:55:03.568Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/37abc4504fa19d8f9f1e87792e8a2b8fdb308e40"},{"url":"https://git.kernel.org/stable/c/e2d4d51cf5785815fa4e91e0c019e3eb2506a84c"},{"url":"https://git.kernel.org/stable/c/de618299190b418291609e6921557253bd417e25"},{"url":"https://git.kernel.org/stable/c/5506c825f14d810f0690b1f4367cb7249ebb387a"},{"url":"https://git.kernel.org/stable/c/542a13890b742099c461d70920e97b14e568f6ec"},{"url":"https://git.kernel.org/stable/c/d548179adcc87e1bc66b17e00352a1f536e76065"},{"url":"https://git.kernel.org/stable/c/3bec49ca55e08fb085cc4318f24b1b37eaab28cb"},{"url":"https://git.kernel.org/stable/c/de21b59c29e31c5108ddc04210631bbfab81b997"}],"title":"thunderbolt: property: Reject dir_len < 4 to prevent size_t underflow","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-63892","datePublished":"2026-07-19T14:55:03.568Z","dateReserved":"2026-07-19T07:54:57.019Z","dateUpdated":"2026-07-19T14:55:03.568Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-19 16:17:06","lastModifiedDate":"2026-07-19 16:17:06","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"63892","Ordinal":"1","Title":"thunderbolt: property: Reject dir_len < 4 to prevent size_t unde","CVE":"CVE-2026-63892","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"63892","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nthunderbolt: property: Reject dir_len < 4 to prevent size_t underflow\n\nOn the non-root path, __tb_property_parse_dir() takes dir_len from\nentry->length (u16 widened to size_t).  Two distinct OOB conditions\nfollow when entry->length < 4:\n\n1. The non-root path begins with kmemdup(&block[dir_offset],\n   sizeof(*dir->uuid), ...) which always reads 4 dwords from\n   dir_offset.  tb_property_entry_valid() only enforces\n   dir_offset + entry->length <= block_len, so a crafted entry\n   with dir_offset close to the end of the property block and\n   entry->length in 0..3 passes that gate but lets the UUID copy\n   run off the block (e.g. dir_offset = 497, dir_len = 3 in a\n   500-dword block reads block[497..501]).\n\n2. After the kmemdup, content_len = dir_len - 4 underflows size_t\n   to ~SIZE_MAX, nentries becomes SIZE_MAX / 4, and the entry\n   walk runs OOB on each iteration until an entry fails\n   validation or the kernel oopses on an unmapped page.\n\nReject dir_len < 4 on the non-root path *before* the UUID kmemdup,\nwhich closes both holes.\n\nAlso move INIT_LIST_HEAD(&dir->properties) up to immediately after\nthe dir allocation so the new error-return path (and the existing\nuuid-alloc failure path) calling tb_property_free_dir() sees a\nwalkable list rather than the zero-initialized NULL next/prev that\nlist_for_each_entry_safe() would oops on.","Type":"Description","Title":"thunderbolt: property: Reject dir_len < 4 to prevent size_t unde"}]}}}