---
id: CVE-2026-64452
title: '6lowpan: fix NHC entry use-after-free on error path'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  6lowpan: fix NHC entry use-after-free on error path

  lowpan_nhc_do_uncompression() looks up an NHC descriptor while holding
  lowpan_nhc_lock.  If the descriptor has no u…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 92aa7c65d295f3cbb96904afe335f683e55584b8 <
    9c2f5c0829a8c8b904dae36be6d8056b719ac605
  - >-
    Linux >= 92aa7c65d295f3cbb96904afe335f683e55584b8 <
    80b5c8779acee0550845394fb3e5176a398aa24c
  - >-
    Linux >= 92aa7c65d295f3cbb96904afe335f683e55584b8 <
    cc27aea4d454abfb385ee2c9499c78b96db9b728
  - >-
    Linux >= 92aa7c65d295f3cbb96904afe335f683e55584b8 <
    a8e3a94711134e898c6021a6b77374efa91b3639
  - >-
    Linux >= 92aa7c65d295f3cbb96904afe335f683e55584b8 <
    593b78bb3c7ef0c6e9ae6fdf5afa80a5f7573168
  - >-
    Linux >= 92aa7c65d295f3cbb96904afe335f683e55584b8 <
    0beccbcf50de125be5520d0ffc59af4bb8655482
  - >-
    Linux >= 92aa7c65d295f3cbb96904afe335f683e55584b8 <
    b713aa0cc344f10f7a9928a230b5f5e780d04078
  - >-
    Linux >= 92aa7c65d295f3cbb96904afe335f683e55584b8 <
    1720db928e5a58ca7d75ac1d514c3b73fd7061a7
  - Linux 4.1
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:41:07.187657Z'
published: '2026-07-25'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:42:37.341Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-64452'
references:
  - url: 'https://git.kernel.org/stable/c/9c2f5c0829a8c8b904dae36be6d8056b719ac605'
  - url: 'https://git.kernel.org/stable/c/80b5c8779acee0550845394fb3e5176a398aa24c'
  - url: 'https://git.kernel.org/stable/c/cc27aea4d454abfb385ee2c9499c78b96db9b728'
  - url: 'https://git.kernel.org/stable/c/a8e3a94711134e898c6021a6b77374efa91b3639'
  - url: 'https://git.kernel.org/stable/c/593b78bb3c7ef0c6e9ae6fdf5afa80a5f7573168'
  - url: 'https://git.kernel.org/stable/c/0beccbcf50de125be5520d0ffc59af4bb8655482'
  - url: 'https://git.kernel.org/stable/c/b713aa0cc344f10f7a9928a230b5f5e780d04078'
  - url: 'https://git.kernel.org/stable/c/1720db928e5a58ca7d75ac1d514c3b73fd7061a7'
tags:
  - cve.org
epss: 0.00219
epssPercentile: 0.11511
ingestedAt: '2026-10-16T17:24:46.822Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

6lowpan: fix NHC entry use-after-free on error path

lowpan_nhc_do_uncompression() looks up an NHC descriptor while holding
lowpan_nhc_lock.  If the descriptor has no uncompress callback, the error
path drops the lock before printing nhc->name.

lowpan_nhc_del() removes descriptors under the same lock and then relies
on synchronize_net() before the owning module can be unloaded.  That only
waits for net RX RCU readers.  lowpan_header_decompress() is also exported
and can be reached from callers that are not necessarily covered by the net
core RX critical section, for example the Bluetooth 6LoWPAN L2CAP receive
path.

This leaves a race where one task drops lowpan_nhc_lock in the error path,
another task unregisters and frees the matching descriptor after
synchronize_net() returns, and the first task then dereferences nhc->name
for the warning.

With the post-unlock window widened, KASAN reports:

  BUG: KASAN: slab-use-after-free in lowpan_nhc_do_uncompression+0x1f4/0x220
  Read of size 8
  lowpan_nhc_do_uncompression
  lowpan_header_decompress

Fix this by printing the warning before dropping lowpan_nhc_lock, so the
descriptor name is read while unregister is still excluded.  The malformed
packet is still rejected with -ENOTSUPP.

## Affected

- `Linux >= 92aa7c65d295f3cbb96904afe335f683e55584b8 < 9c2f5c0829a8c8b904dae36be6d8056b719ac605`
- `Linux >= 92aa7c65d295f3cbb96904afe335f683e55584b8 < 80b5c8779acee0550845394fb3e5176a398aa24c`
- `Linux >= 92aa7c65d295f3cbb96904afe335f683e55584b8 < cc27aea4d454abfb385ee2c9499c78b96db9b728`
- `Linux >= 92aa7c65d295f3cbb96904afe335f683e55584b8 < a8e3a94711134e898c6021a6b77374efa91b3639`
- `Linux >= 92aa7c65d295f3cbb96904afe335f683e55584b8 < 593b78bb3c7ef0c6e9ae6fdf5afa80a5f7573168`
- `Linux >= 92aa7c65d295f3cbb96904afe335f683e55584b8 < 0beccbcf50de125be5520d0ffc59af4bb8655482`
- `Linux >= 92aa7c65d295f3cbb96904afe335f683e55584b8 < b713aa0cc344f10f7a9928a230b5f5e780d04078`
- `Linux >= 92aa7c65d295f3cbb96904afe335f683e55584b8 < 1720db928e5a58ca7d75ac1d514c3b73fd7061a7`
- `Linux 4.1`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.