ntfs3: validate split-point offset in indx_insert_into_buffer

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-72191
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 06:21:37 UTC
Updated2026-08-23 13:16:41 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: ntfs3: validate split-point offset in indx_insert_into_buffer indx_insert_into_buffer() computes used = used1 - to_copy - sp_size; memmove(de_t, Add2Ptr(sp, sp_size), used - le32_to_cpu(hdr1->de_off)); where sp and sp_size come from hdr_find_split(). hdr_find_split() walks entries by le16_to_cpu(e->size) without validating that each step stays within hdr->used or that the size field is at least sizeof(struct NTFS_DE). index_hdr_check(), the on-load gatekeeper, only validates header-level fields (used, total, de_off) and does not walk per-entry sizes. A crafted NTFS image whose leaf INDEX_HDR reports used == total but contains one interior NTFS_DE with size = 0xFFF0 therefore passes validation, descends to indx_insert_into_buffer() through the ntfs_create() -> indx_insert_entry() path, and makes hdr_find_split() return an sp whose sp_size (0xFFF0) greatly exceeds the remaining bytes in the buffer. The u32 subtraction underflows and the memmove count becomes a near-4-GiB value, producing an out-of-bounds kernel write that corrupts adjacent allocations and panics the kernel. Reproduced on 7.0.0-rc7 with UML + KASAN via a crafted image and a single 'touch' inside the mounted directory; crash site resolves to fs/ntfs3/index.c at the memmove. Trigger requires only local mount of an attacker-supplied filesystem image (USB, loopback, or removable media auto-mount). Reject the split whenever the chosen sp plus its declared size already extends past hdr1->used. This is the minimal fix; it preserves the existing hdr_find_split() contract and relies on the same out: cleanup path as the pre-existing error returns. A prior OOB read in the very same indx_insert_into_buffer() memmove was fixed in commit b8c44949044e ("fs/ntfs3: Fix OOB read in indx_insert_into_buffer") by tightening hdr_find_e(), but that fix does not cover the split-point size field path addressed here: sp is returned by hdr_find_split(), not hdr_find_e(), and the underflow is driven by sp->size rather than hdr->used exceeding hdr->total.

Risk And Classification

Primary CVSS: v3.1 9.8 CRITICAL from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.006180000 probability, percentile 0.466950000 (date 2026-08-17)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 82cae269cfa953032fbb8980a7d554d60fb00b17 8e4ba5a38c155bb3c1c11e63cd285b178cdb099e git Not specified
CNA Linux Linux affected 82cae269cfa953032fbb8980a7d554d60fb00b17 4c2f648139a0a86f4486170f72e24fedd4fae74e git Not specified
CNA Linux Linux affected 82cae269cfa953032fbb8980a7d554d60fb00b17 b232eb5c9fe11ec2368e9b565db69c724c35fbd2 git Not specified
CNA Linux Linux affected 82cae269cfa953032fbb8980a7d554d60fb00b17 7bf74e6baf810fe325f111996496c678fc6e244f git Not specified
CNA Linux Linux affected 82cae269cfa953032fbb8980a7d554d60fb00b17 f3624cc069195001c88df7a291af215f2133ff2c git Not specified
CNA Linux Linux affected 82cae269cfa953032fbb8980a7d554d60fb00b17 1758a564b6ebe7f4a82f23c9851d1cae15549457 git Not specified
CNA Linux Linux affected 82cae269cfa953032fbb8980a7d554d60fb00b17 f1df9d771df47aa40de6d70949c28720ae1e430d git Not specified
CNA Linux Linux affected 5.15 Not specified
CNA Linux Linux unaffected 5.15 semver Not specified
CNA Linux Linux unaffected 5.15.217 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.184 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.145 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.97 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.40 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.5 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/f1df9d771df47aa40de6d70949c28720ae1e430d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/4c2f648139a0a86f4486170f72e24fedd4fae74e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/8e4ba5a38c155bb3c1c11e63cd285b178cdb099e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/7bf74e6baf810fe325f111996496c678fc6e244f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f3624cc069195001c88df7a291af215f2133ff2c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/1758a564b6ebe7f4a82f23c9851d1cae15549457 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b232eb5c9fe11ec2368e9b565db69c724c35fbd2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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