{"id":"CVE-2026-72192","summary":"ntfs3: bound to_move in indx_insert_into_root before hdr_insert_head","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nntfs3: bound to_move in indx_insert_into_root before hdr_insert_head\n\nindx_insert_into_root() promotes a full resident $INDEX_ROOT into\n$INDEX_ALLOCATION and copies all non-last resident root entries into\na newly allocated INDEX_BUFFER via hdr_insert_head(). The source\nbyte count 'to_move' is summed from the on-disk resident entry sizes\nand is independent of the destination buffer size, which comes from\nroot-\u003eindex_block_size (via indx-\u003eindex_bits).\n\nA crafted NTFS image that keeps a valid, full resident root but\nshrinks root-\u003eindex_block_size down to 512 after the root has been\npopulated makes hdr_insert_head() memcpy attacker-controlled resident\nentry bytes past the end of the kmalloc(1u \u003c\u003c indx-\u003eindex_bits)\nallocation returned by indx_new(). For a 512-byte destination and a\nresident root whose non-last entries total 560 bytes, the memcpy\noverruns by 120 bytes and a following memmove extends the highest\nwritten offset to 136 bytes past the allocation. The overflow bytes\nare a direct copy of on-disk entries (via kmemdup), so they are\nfully attacker-controlled.\n\nThe write is reachable from unprivileged open(O_CREAT) on a mounted\ncrafted NTFS image: a single sufficiently long create in a directory\nwhose resident root is already full forces root promotion and\ntriggers the copy.\n\nThis is a controlled out-of-bounds write of 120-136 bytes past a\nkmalloc(index_block_size) allocation, with attacker-controlled\ncontent. It is a bounded adjacent-heap corruption primitive; it is\nnot an arbitrary-address write. Successful exploitation into a named\nvictim object depends on the surrounding slab layout.\n\nReject the copy at the sink. The destination's INDEX_HDR already\nreports hdr_total (the payload capacity of the new buffer) and\nhdr_used (the bytes already consumed by the terminal END entry\ninstalled by indx_new()); require that to_move fits in the remaining\npayload before calling hdr_insert_head(). On mismatch, fail with\n-EINVAL and mark the filesystem as having a detected on-disk\ninconsistency, which is the same behaviour as the surrounding\nvalidation in this function.","modified":"2026-08-18T03:56:38.547489790Z","published":"2026-08-15T05:53:52.634Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72192.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0af83b8155cc848e9f5d2c36e20a70d024214649"},{"type":"WEB","url":"https://git.kernel.org/stable/c/194b00c99ba971fa7cf6acd747a36032c6de54eb"},{"type":"WEB","url":"https://git.kernel.org/stable/c/53c5f3b2da3774b41534728aba295c098c9efa19"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9b6926ac9c970ae0b2c2fe6289b16e9aa10b6a67"},{"type":"WEB","url":"https://git.kernel.org/stable/c/aaa1f956c0fc41089a4a534da7df91552a08a47c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/cb3161deebcaf8d36d3115abf452c633f2180fc1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d240f5f9d036b8180224954d9873f172b6be4dd8"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72192.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72192"},{"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":"82cae269cfa953032fbb8980a7d554d60fb00b17"},{"fixed":"0af83b8155cc848e9f5d2c36e20a70d024214649"},{"fixed":"cb3161deebcaf8d36d3115abf452c633f2180fc1"},{"fixed":"53c5f3b2da3774b41534728aba295c098c9efa19"},{"fixed":"194b00c99ba971fa7cf6acd747a36032c6de54eb"},{"fixed":"aaa1f956c0fc41089a4a534da7df91552a08a47c"},{"fixed":"d240f5f9d036b8180224954d9873f172b6be4dd8"},{"fixed":"9b6926ac9c970ae0b2c2fe6289b16e9aa10b6a67"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72192.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.15.0"},{"fixed":"5.15.212"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.178"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.145"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.97"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.40"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72192.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}