---
id: CVE-2026-98457
title: 'Bluetooth: L2CAP: validate frame length before control and FCS access'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  Bluetooth: L2CAP: validate frame length before control and FCS access

  l2cap_data_rcv() unpacks either a two-byte or four-byte control field
  without first ensuring that…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1c2acffb76d4bc5fd27c4ea55cc27ad8ead10f9a <
    4373ba79a267947e771c438507f7b103e30bdb21
  - >-
    Linux >= 1c2acffb76d4bc5fd27c4ea55cc27ad8ead10f9a <
    965bd88ed4b4763cb765dd65885adcfa588c6b14
  - >-
    Linux >= 1c2acffb76d4bc5fd27c4ea55cc27ad8ead10f9a <
    3acf6a0038ec0d4e8f4dcbfc2a557dff5f61cb70
  - >-
    Linux >= 1c2acffb76d4bc5fd27c4ea55cc27ad8ead10f9a <
    8c7556c7cd17e073bbefdc4a9a4694a207544c37
  - >-
    Linux >= 1c2acffb76d4bc5fd27c4ea55cc27ad8ead10f9a <
    1fdbb2a712a9a162ee817c959740face80b3d929
  - >-
    Linux >= 1c2acffb76d4bc5fd27c4ea55cc27ad8ead10f9a <
    c6a288e6001bcce16553c3853e0f5a45eaaf85c7
  - >-
    Linux >= 1c2acffb76d4bc5fd27c4ea55cc27ad8ead10f9a <
    f557274af7b94b6134692e6f26b880f1e34c15bf
  - >-
    Linux >= 1c2acffb76d4bc5fd27c4ea55cc27ad8ead10f9a <
    6c78a213d9070b610c7f418af2c25b66180b7e37
  - Linux 2.6.32
published: '2026-10-18'
updated: '2026-10-18'
sourceUpdated: '2026-10-18T15:15:06.718Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98457'
references:
  - url: 'https://git.kernel.org/stable/c/4373ba79a267947e771c438507f7b103e30bdb21'
  - url: 'https://git.kernel.org/stable/c/965bd88ed4b4763cb765dd65885adcfa588c6b14'
  - url: 'https://git.kernel.org/stable/c/3acf6a0038ec0d4e8f4dcbfc2a557dff5f61cb70'
  - url: 'https://git.kernel.org/stable/c/8c7556c7cd17e073bbefdc4a9a4694a207544c37'
  - url: 'https://git.kernel.org/stable/c/1fdbb2a712a9a162ee817c959740face80b3d929'
  - url: 'https://git.kernel.org/stable/c/c6a288e6001bcce16553c3853e0f5a45eaaf85c7'
  - url: 'https://git.kernel.org/stable/c/f557274af7b94b6134692e6f26b880f1e34c15bf'
  - url: 'https://git.kernel.org/stable/c/6c78a213d9070b610c7f418af2c25b66180b7e37'
tags:
  - cve.org
ingestedAt: '2026-10-18T15:45:12.304Z'
---

## Overview

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

Bluetooth: L2CAP: validate frame length before control and FCS access

l2cap_data_rcv() unpacks either a two-byte or four-byte control field
without first ensuring that it is present. A short ERTM or streaming-mode
frame can therefore cause an out-of-bounds read.

There is a second short-frame case when CRC16 is enabled. After the
control field is pulled, l2cap_check_fcs() subtracts two from skb->len
without checking it. If fewer than two bytes remain, the subtraction
wraps; skb_trim() leaves the buffer unchanged and the subsequent FCS
load reads past the logical end of the frame.

Validate that the frame contains both its control field and, when
enabled, its FCS before either field is accessed.

## Affected

- `Linux >= 1c2acffb76d4bc5fd27c4ea55cc27ad8ead10f9a < 4373ba79a267947e771c438507f7b103e30bdb21`
- `Linux >= 1c2acffb76d4bc5fd27c4ea55cc27ad8ead10f9a < 965bd88ed4b4763cb765dd65885adcfa588c6b14`
- `Linux >= 1c2acffb76d4bc5fd27c4ea55cc27ad8ead10f9a < 3acf6a0038ec0d4e8f4dcbfc2a557dff5f61cb70`
- `Linux >= 1c2acffb76d4bc5fd27c4ea55cc27ad8ead10f9a < 8c7556c7cd17e073bbefdc4a9a4694a207544c37`
- `Linux >= 1c2acffb76d4bc5fd27c4ea55cc27ad8ead10f9a < 1fdbb2a712a9a162ee817c959740face80b3d929`
- `Linux >= 1c2acffb76d4bc5fd27c4ea55cc27ad8ead10f9a < c6a288e6001bcce16553c3853e0f5a45eaaf85c7`
- `Linux >= 1c2acffb76d4bc5fd27c4ea55cc27ad8ead10f9a < f557274af7b94b6134692e6f26b880f1e34c15bf`
- `Linux >= 1c2acffb76d4bc5fd27c4ea55cc27ad8ead10f9a < 6c78a213d9070b610c7f418af2c25b66180b7e37`
- `Linux 2.6.32`

## Remediation

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