{"id":"CVE-2026-90133","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: Fix index_root heap OOB write in ntfs_ir_to_ib()\n\nntfs_ir_to_ib copies all entries from index_root into a freshly allocated\nindex_block_size-byte buffer without v…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: Fix index_root heap OOB write in ntfs_ir_to_ib()\n\nntfs_ir_to_ib copies all entries from index_root into a freshly allocated\nindex_block_size-byte buffer without v…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","vendor":"Linux","product":"Linux","affected":["Linux >= 0a8ac0c1fa0b99a5b29002bc7f232ed7eafddef0 < 825dec5120933e90c54e30e31ccfa6c3449043a8","Linux >= 0a8ac0c1fa0b99a5b29002bc7f232ed7eafddef0 < dc09bf79b76f9a7157e225f449655f3f62f96c9c","Linux 7.1"],"published":"2026-09-17","updated":"2026-09-18","sourceUpdated":"2026-09-18T18:17:43.133","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-90133","references":[{"url":"https://git.kernel.org/stable/c/825dec5120933e90c54e30e31ccfa6c3449043a8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/dc09bf79b76f9a7157e225f449655f3f62f96c9c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"epss":0.00191,"epssPercentile":0.08988,"ingestedAt":"2026-09-17T16:21:47.880Z","slug":"CVE-2026-90133","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nntfs: Fix index_root heap OOB write in ntfs_ir_to_ib()\n\nntfs_ir_to_ib copies all entries from index_root into a freshly allocated\nindex_block_size-byte buffer without verifying that the entries fit in the\navailable space. The entries in index_root may be larger than the usable\nentry space in the index block.\n\nThis can cause OOB writes past the end of the allocation.\n\nThe validator ntfs_index_root_inconsistent() checks that entries are\nself-consistent within the IR value, but never cross-checks them against\nindex_block_size. There is no bounds check in ntfs_ir_to_ib() before the\nmemcpy.\n\nFixing this at the sink in ntfs_ir_to_ib() since\nntfs_index_root_inconsistent() validates the logical consistency of\nindex_root as a structure and a root with large entries is a structurally\nvalid root. The bug is a size conflict of ntfs_ir_to_ib().\nAlso, the validator is called once per inode load in\nntfs_read_locked_inode() while ntfs_ir_to_ib() is only called during a\nreparent, a check there adds no overhead to the common path.\nMoreover, even a future call path that bypasses the validator would still\nbe protected.\n\nWith NULL as first parameter of ntfs_error(), the volume error flag is\nnever set by this call, so the device name will be absent from the error\nmessage. In any case, that the caller, ntfs_ir_reparent(), prints an error\nmessage that includes the device name on NULL returns.\nI think this is the best solution available without adding\n'struct super_block *sb' as a parameter to ntfs_ir_to_ib().\n\nThis heap out-of-bounds write is triggered by a crafted filesystem image,\nwhich is not in the kernel threat model, anyway, fixing memory errors would\nbe nice to keep  things secure.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":207135,"id":"CVE-2026-90133","ts":1789757334918,"field":"cvss","old":null,"new":"7.8"},{"seq":207134,"id":"CVE-2026-90133","ts":1789757334918,"field":"severity","old":"none","new":"high"}]}