GHSA-JF9F-9V3Q-F4C9
Vulnerability from github – Published: 2026-09-17 18:31 – Updated: 2026-09-18 18:31In the Linux kernel, the following vulnerability has been resolved:
ntfs: Fix index_root heap OOB write in ntfs_ir_to_ib()
ntfs_ir_to_ib copies all entries from index_root into a freshly allocated index_block_size-byte buffer without verifying that the entries fit in the available space. The entries in index_root may be larger than the usable entry space in the index block.
This can cause OOB writes past the end of the allocation.
The validator ntfs_index_root_inconsistent() checks that entries are self-consistent within the IR value, but never cross-checks them against index_block_size. There is no bounds check in ntfs_ir_to_ib() before the memcpy.
Fixing this at the sink in ntfs_ir_to_ib() since ntfs_index_root_inconsistent() validates the logical consistency of index_root as a structure and a root with large entries is a structurally valid root. The bug is a size conflict of ntfs_ir_to_ib(). Also, the validator is called once per inode load in ntfs_read_locked_inode() while ntfs_ir_to_ib() is only called during a reparent, a check there adds no overhead to the common path. Moreover, even a future call path that bypasses the validator would still be protected.
With NULL as first parameter of ntfs_error(), the volume error flag is never set by this call, so the device name will be absent from the error message. In any case, that the caller, ntfs_ir_reparent(), prints an error message that includes the device name on NULL returns. I think this is the best solution available without adding 'struct super_block *sb' as a parameter to ntfs_ir_to_ib().
This heap out-of-bounds write is triggered by a crafted filesystem image, which is not in the kernel threat model, anyway, fixing memory errors would be nice to keep things secure.
{
"affected": [],
"aliases": [
"CVE-2026-90133"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-17T17:17:05Z",
"severity": "HIGH"
},
"details": "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 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\u0027struct super_block *sb\u0027 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.",
"id": "GHSA-jf9f-9v3q-f4c9",
"modified": "2026-09-18T18:31:27Z",
"published": "2026-09-17T18:31:52Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90133"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/825dec5120933e90c54e30e31ccfa6c3449043a8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/dc09bf79b76f9a7157e225f449655f3f62f96c9c"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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