{"api_version":"1","generated_at":"2026-07-23T17:56:43+00:00","cve":"CVE-2026-63891","urls":{"html":"https://cve.report/CVE-2026-63891","api":"https://cve.report/api/cve/CVE-2026-63891.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-63891","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-63891"},"summary":{"title":"thunderbolt: property: Cap recursion depth in __tb_property_parse_dir()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nthunderbolt: property: Cap recursion depth in __tb_property_parse_dir()\n\nA DIRECTORY entry's value field is used as the dir_offset for a\nrecursive call into __tb_property_parse_dir() with no depth counter.\nA crafted peer that chains DIRECTORY entries into a back-reference\nloop drives the parser until the kernel stack is exhausted and the\nguard page fires.  Any untrusted XDomain peer (cable, dock, in-line\ninspector, adjacent host) that reaches the PROPERTIES_REQUEST\ncontrol-plane exchange can trigger this without authentication.\n\nThread a depth counter through tb_property_parse() and\n__tb_property_parse_dir(), and reject blocks that exceed\nTB_PROPERTY_MAX_DEPTH = 8.  That is comfortably larger than any\nobserved legitimate XDomain layout.\n\nOperators who do not need XDomain host-to-host discovery can disable\nthe path entirely with thunderbolt.xdomain=0 on the kernel command\nline.","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/b4621e5ef63405c317a84b711faf3bd75b3c6a94","name":"https://git.kernel.org/stable/c/b4621e5ef63405c317a84b711faf3bd75b3c6a94","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ed9455ef4bd9babc90f92e526abe3fb68c1a8709","name":"https://git.kernel.org/stable/c/ed9455ef4bd9babc90f92e526abe3fb68c1a8709","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/928abe19fbf0127003abcb1ea69cabc1c897d0ab","name":"https://git.kernel.org/stable/c/928abe19fbf0127003abcb1ea69cabc1c897d0ab","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0a84ab9271936c11e84e511bb52fc5682f8b6726","name":"https://git.kernel.org/stable/c/0a84ab9271936c11e84e511bb52fc5682f8b6726","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f31c6d220f455b5af63590302b30e1b932d14599","name":"https://git.kernel.org/stable/c/f31c6d220f455b5af63590302b30e1b932d14599","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2b5f47a710172c962ef42d1b732b04d2ad0dce21","name":"https://git.kernel.org/stable/c/2b5f47a710172c962ef42d1b732b04d2ad0dce21","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/830c8a9b467e7d3a158483d37fa7dc13892b293a","name":"https://git.kernel.org/stable/c/830c8a9b467e7d3a158483d37fa7dc13892b293a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/95839a67ea56ca35732aad7f711404a3127cfe2d","name":"https://git.kernel.org/stable/c/95839a67ea56ca35732aad7f711404a3127cfe2d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-63891","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63891","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cdae7c07e3e3509eaabc18c1640a55dc5b99c179 2b5f47a710172c962ef42d1b732b04d2ad0dce21 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cdae7c07e3e3509eaabc18c1640a55dc5b99c179 95839a67ea56ca35732aad7f711404a3127cfe2d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cdae7c07e3e3509eaabc18c1640a55dc5b99c179 0a84ab9271936c11e84e511bb52fc5682f8b6726 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cdae7c07e3e3509eaabc18c1640a55dc5b99c179 b4621e5ef63405c317a84b711faf3bd75b3c6a94 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":"63891","cve":"CVE-2026-63891","epss":"0.002630000","percentile":"0.179640000","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":"2b5f47a710172c962ef42d1b732b04d2ad0dce21","status":"affected","version":"cdae7c07e3e3509eaabc18c1640a55dc5b99c179","versionType":"git"},{"lessThan":"95839a67ea56ca35732aad7f711404a3127cfe2d","status":"affected","version":"cdae7c07e3e3509eaabc18c1640a55dc5b99c179","versionType":"git"},{"lessThan":"0a84ab9271936c11e84e511bb52fc5682f8b6726","status":"affected","version":"cdae7c07e3e3509eaabc18c1640a55dc5b99c179","versionType":"git"},{"lessThan":"b4621e5ef63405c317a84b711faf3bd75b3c6a94","status":"affected","version":"cdae7c07e3e3509eaabc18c1640a55dc5b99c179","versionType":"git"},{"lessThan":"f31c6d220f455b5af63590302b30e1b932d14599","status":"affected","version":"cdae7c07e3e3509eaabc18c1640a55dc5b99c179","versionType":"git"},{"lessThan":"830c8a9b467e7d3a158483d37fa7dc13892b293a","status":"affected","version":"cdae7c07e3e3509eaabc18c1640a55dc5b99c179","versionType":"git"},{"lessThan":"ed9455ef4bd9babc90f92e526abe3fb68c1a8709","status":"affected","version":"cdae7c07e3e3509eaabc18c1640a55dc5b99c179","versionType":"git"},{"lessThan":"928abe19fbf0127003abcb1ea69cabc1c897d0ab","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: Cap recursion depth in __tb_property_parse_dir()\n\nA DIRECTORY entry's value field is used as the dir_offset for a\nrecursive call into __tb_property_parse_dir() with no depth counter.\nA crafted peer that chains DIRECTORY entries into a back-reference\nloop drives the parser until the kernel stack is exhausted and the\nguard page fires.  Any untrusted XDomain peer (cable, dock, in-line\ninspector, adjacent host) that reaches the PROPERTIES_REQUEST\ncontrol-plane exchange can trigger this without authentication.\n\nThread a depth counter through tb_property_parse() and\n__tb_property_parse_dir(), and reject blocks that exceed\nTB_PROPERTY_MAX_DEPTH = 8.  That is comfortably larger than any\nobserved legitimate XDomain layout.\n\nOperators who do not need XDomain host-to-host discovery can disable\nthe path entirely with thunderbolt.xdomain=0 on the kernel command\nline."}],"providerMetadata":{"dateUpdated":"2026-07-19T14:55:02.840Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/2b5f47a710172c962ef42d1b732b04d2ad0dce21"},{"url":"https://git.kernel.org/stable/c/95839a67ea56ca35732aad7f711404a3127cfe2d"},{"url":"https://git.kernel.org/stable/c/0a84ab9271936c11e84e511bb52fc5682f8b6726"},{"url":"https://git.kernel.org/stable/c/b4621e5ef63405c317a84b711faf3bd75b3c6a94"},{"url":"https://git.kernel.org/stable/c/f31c6d220f455b5af63590302b30e1b932d14599"},{"url":"https://git.kernel.org/stable/c/830c8a9b467e7d3a158483d37fa7dc13892b293a"},{"url":"https://git.kernel.org/stable/c/ed9455ef4bd9babc90f92e526abe3fb68c1a8709"},{"url":"https://git.kernel.org/stable/c/928abe19fbf0127003abcb1ea69cabc1c897d0ab"}],"title":"thunderbolt: property: Cap recursion depth in __tb_property_parse_dir()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-63891","datePublished":"2026-07-19T14:55:02.840Z","dateReserved":"2026-07-19T07:54:57.019Z","dateUpdated":"2026-07-19T14:55:02.840Z","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":"63891","Ordinal":"1","Title":"thunderbolt: property: Cap recursion depth in __tb_property_pars","CVE":"CVE-2026-63891","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"63891","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nthunderbolt: property: Cap recursion depth in __tb_property_parse_dir()\n\nA DIRECTORY entry's value field is used as the dir_offset for a\nrecursive call into __tb_property_parse_dir() with no depth counter.\nA crafted peer that chains DIRECTORY entries into a back-reference\nloop drives the parser until the kernel stack is exhausted and the\nguard page fires.  Any untrusted XDomain peer (cable, dock, in-line\ninspector, adjacent host) that reaches the PROPERTIES_REQUEST\ncontrol-plane exchange can trigger this without authentication.\n\nThread a depth counter through tb_property_parse() and\n__tb_property_parse_dir(), and reject blocks that exceed\nTB_PROPERTY_MAX_DEPTH = 8.  That is comfortably larger than any\nobserved legitimate XDomain layout.\n\nOperators who do not need XDomain host-to-host discovery can disable\nthe path entirely with thunderbolt.xdomain=0 on the kernel command\nline.","Type":"Description","Title":"thunderbolt: property: Cap recursion depth in __tb_property_pars"}]}}}