{"id":"CVE-2026-72191","title":"ntfs3: validate split-point offset in indx_insert_into_buffer","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nntfs3: validate split-point offset in indx_insert_into_buffer\n\nindx_insert_into_buffer() computes\n\n    used = used1 - to_copy - sp_size;\n    memmove(de_t, Add2Ptr(sp, s…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 82cae269cfa953032fbb8980a7d554d60fb00b17 < 8e4ba5a38c155bb3c1c11e63cd285b178cdb099e","Linux >= 82cae269cfa953032fbb8980a7d554d60fb00b17 < 4c2f648139a0a86f4486170f72e24fedd4fae74e","Linux >= 82cae269cfa953032fbb8980a7d554d60fb00b17 < b232eb5c9fe11ec2368e9b565db69c724c35fbd2","Linux >= 82cae269cfa953032fbb8980a7d554d60fb00b17 < 7bf74e6baf810fe325f111996496c678fc6e244f","Linux >= 82cae269cfa953032fbb8980a7d554d60fb00b17 < f3624cc069195001c88df7a291af215f2133ff2c","Linux >= 82cae269cfa953032fbb8980a7d554d60fb00b17 < 1758a564b6ebe7f4a82f23c9851d1cae15549457","Linux >= 82cae269cfa953032fbb8980a7d554d60fb00b17 < f1df9d771df47aa40de6d70949c28720ae1e430d","Linux 5.15"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-10-16T18:43:30.355468Z"},"published":"2026-08-15","updated":"2026-10-16","sourceUpdated":"2026-10-16T18:45:00.783Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72191","references":[{"url":"https://git.kernel.org/stable/c/8e4ba5a38c155bb3c1c11e63cd285b178cdb099e"},{"url":"https://git.kernel.org/stable/c/4c2f648139a0a86f4486170f72e24fedd4fae74e"},{"url":"https://git.kernel.org/stable/c/b232eb5c9fe11ec2368e9b565db69c724c35fbd2"},{"url":"https://git.kernel.org/stable/c/7bf74e6baf810fe325f111996496c678fc6e244f"},{"url":"https://git.kernel.org/stable/c/f3624cc069195001c88df7a291af215f2133ff2c"},{"url":"https://git.kernel.org/stable/c/1758a564b6ebe7f4a82f23c9851d1cae15549457"},{"url":"https://git.kernel.org/stable/c/f1df9d771df47aa40de6d70949c28720ae1e430d"}],"tags":["cve.org"],"epss":0.00697,"epssPercentile":0.52104,"ingestedAt":"2026-10-16T19:46:24.423Z","slug":"CVE-2026-72191","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nntfs3: validate split-point offset in indx_insert_into_buffer\n\nindx_insert_into_buffer() computes\n\n    used = used1 - to_copy - sp_size;\n    memmove(de_t, Add2Ptr(sp, sp_size), used - le32_to_cpu(hdr1->de_off));\n\nwhere sp and sp_size come from hdr_find_split().  hdr_find_split()\nwalks entries by le16_to_cpu(e->size) without validating that each\nstep stays within hdr->used or that the size field is at least\nsizeof(struct NTFS_DE).  index_hdr_check(), the on-load gatekeeper,\nonly validates header-level fields (used, total, de_off) and does\nnot walk per-entry sizes.\n\nA crafted NTFS image whose leaf INDEX_HDR reports used == total but\ncontains one interior NTFS_DE with size = 0xFFF0 therefore passes\nvalidation, descends to indx_insert_into_buffer() through the\nntfs_create() -> indx_insert_entry() path, and makes hdr_find_split()\nreturn an sp whose sp_size (0xFFF0) greatly exceeds the remaining\nbytes in the buffer.  The u32 subtraction underflows and the memmove\ncount becomes a near-4-GiB value, producing an out-of-bounds kernel\nwrite that corrupts adjacent allocations and panics the kernel.\n\nReproduced on 7.0.0-rc7 with UML + KASAN via a crafted image and a\nsingle 'touch' inside the mounted directory; crash site resolves to\nfs/ntfs3/index.c at the memmove.  Trigger requires only local mount\nof an attacker-supplied filesystem image (USB, loopback, or removable\nmedia auto-mount).\n\nReject the split whenever the chosen sp plus its declared size\nalready extends past hdr1->used.  This is the minimal fix; it\npreserves the existing hdr_find_split() contract and relies on the\nsame out: cleanup path as the pre-existing error returns.\n\nA prior OOB read in the very same indx_insert_into_buffer() memmove\nwas fixed in commit b8c44949044e (\"fs/ntfs3: Fix OOB read in\nindx_insert_into_buffer\") by tightening hdr_find_e(), but that fix\ndoes not cover the split-point size field path addressed here: sp is\nreturned by hdr_find_split(), not hdr_find_e(), and the underflow is\ndriven by sp->size rather than hdr->used exceeding hdr->total.\n\n## Affected\n\n- `Linux >= 82cae269cfa953032fbb8980a7d554d60fb00b17 < 8e4ba5a38c155bb3c1c11e63cd285b178cdb099e`\n- `Linux >= 82cae269cfa953032fbb8980a7d554d60fb00b17 < 4c2f648139a0a86f4486170f72e24fedd4fae74e`\n- `Linux >= 82cae269cfa953032fbb8980a7d554d60fb00b17 < b232eb5c9fe11ec2368e9b565db69c724c35fbd2`\n- `Linux >= 82cae269cfa953032fbb8980a7d554d60fb00b17 < 7bf74e6baf810fe325f111996496c678fc6e244f`\n- `Linux >= 82cae269cfa953032fbb8980a7d554d60fb00b17 < f3624cc069195001c88df7a291af215f2133ff2c`\n- `Linux >= 82cae269cfa953032fbb8980a7d554d60fb00b17 < 1758a564b6ebe7f4a82f23c9851d1cae15549457`\n- `Linux >= 82cae269cfa953032fbb8980a7d554d60fb00b17 < f1df9d771df47aa40de6d70949c28720ae1e430d`\n- `Linux 5.15`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}