{"id":"CVE-2026-63891","summary":"thunderbolt: property: Cap recursion depth in __tb_property_parse_dir()","details":"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.","modified":"2026-07-21T03:47:31.694805306Z","published":"2026-07-19T14:55:02.840Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63891.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0a84ab9271936c11e84e511bb52fc5682f8b6726"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2b5f47a710172c962ef42d1b732b04d2ad0dce21"},{"type":"WEB","url":"https://git.kernel.org/stable/c/830c8a9b467e7d3a158483d37fa7dc13892b293a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/928abe19fbf0127003abcb1ea69cabc1c897d0ab"},{"type":"WEB","url":"https://git.kernel.org/stable/c/95839a67ea56ca35732aad7f711404a3127cfe2d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b4621e5ef63405c317a84b711faf3bd75b3c6a94"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ed9455ef4bd9babc90f92e526abe3fb68c1a8709"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f31c6d220f455b5af63590302b30e1b932d14599"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63891.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63891"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"cdae7c07e3e3509eaabc18c1640a55dc5b99c179"},{"fixed":"2b5f47a710172c962ef42d1b732b04d2ad0dce21"},{"fixed":"95839a67ea56ca35732aad7f711404a3127cfe2d"},{"fixed":"0a84ab9271936c11e84e511bb52fc5682f8b6726"},{"fixed":"b4621e5ef63405c317a84b711faf3bd75b3c6a94"},{"fixed":"f31c6d220f455b5af63590302b30e1b932d14599"},{"fixed":"830c8a9b467e7d3a158483d37fa7dc13892b293a"},{"fixed":"ed9455ef4bd9babc90f92e526abe3fb68c1a8709"},{"fixed":"928abe19fbf0127003abcb1ea69cabc1c897d0ab"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63891.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.15.0"},{"fixed":"5.10.259"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.210"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.176"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.143"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.93"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.35"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.12"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63891.json"}}],"schema_version":"1.7.5"}