---
id: CVE-2026-80827
title: 'USB: serial: option: fix slab OOB read in interrupt URB callback'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  USB: serial: option: fix slab OOB read in interrupt URB callback

  The interrupt URB buffer is allocated in setup_port_interrupt_in() based
  on the endpoint's wMaxPacketS…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 <
    fbe60fd2abc8a5561f39719a41ad9a01b5d8e567
  - >-
    Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 <
    94e5525697b9e91ddc4071129874120a50a4f342
  - >-
    Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 <
    6b8cf5422c7e96ed5b22a8368eff663f3f98b8ec
  - >-
    Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 <
    030e3a73d3c3aa67c44454649e984d6383cdb7d3
  - >-
    Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 <
    060db7d48af1e650643c8b8319111a9ea2ce4486
  - >-
    Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 <
    2ef5560387f2c0713cee975be2b24b281bd90f3e
  - >-
    Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 <
    a72a13c83a652516a0e469d275b81d29a7429049
  - >-
    Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 <
    d762aef4eba354066be21a5d88eb2066e282f4c9
  - >-
    Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 <
    885d802f544ca7bfa8f3984d94233cce715bb6b3
  - Linux 2.6.12
published: '2026-09-04'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:44:19.753Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-80827'
references:
  - url: 'https://git.kernel.org/stable/c/fbe60fd2abc8a5561f39719a41ad9a01b5d8e567'
  - url: 'https://git.kernel.org/stable/c/94e5525697b9e91ddc4071129874120a50a4f342'
  - url: 'https://git.kernel.org/stable/c/6b8cf5422c7e96ed5b22a8368eff663f3f98b8ec'
  - url: 'https://git.kernel.org/stable/c/030e3a73d3c3aa67c44454649e984d6383cdb7d3'
  - url: 'https://git.kernel.org/stable/c/060db7d48af1e650643c8b8319111a9ea2ce4486'
  - url: 'https://git.kernel.org/stable/c/2ef5560387f2c0713cee975be2b24b281bd90f3e'
  - url: 'https://git.kernel.org/stable/c/a72a13c83a652516a0e469d275b81d29a7429049'
  - url: 'https://git.kernel.org/stable/c/d762aef4eba354066be21a5d88eb2066e282f4c9'
  - url: 'https://git.kernel.org/stable/c/885d802f544ca7bfa8f3984d94233cce715bb6b3'
tags:
  - cve.org
epss: 0.00195
epssPercentile: 0.08588
ingestedAt: '2026-10-19T09:16:01.502Z'
---

## Overview

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

USB: serial: option: fix slab OOB read in interrupt URB callback

The interrupt URB buffer is allocated in setup_port_interrupt_in() based
on the endpoint's wMaxPacketSize:

    buffer_size = usb_endpoint_maxp(epd);
    port->interrupt_in_buffer = kmalloc(buffer_size, GFP_KERNEL);

When a USB device declares wMaxPacketSize = 8 on its interrupt IN
endpoint, the buffer is allocated from kmalloc-8 cache (exactly
8 bytes).

If the device sends a short packet (actual_length < wMaxPacketSize),
the URB completes with status == 0 and the callback proceeds to read:

    data[sizeof(struct usb_ctrlrequest)]

which evaluates to data[8], accessing 1 byte beyond the allocated 8-byte
buffer. This results in a slab out-of-bounds read.

Fix this by adding the missing bounds check: first verify that the
actual length is large enough to contain the struct usb_ctrlrequest
header before accessing req_pkt->bRequestType and req_pkt->bRequest,
and then verify that there is an additional byte for the modem signal
state before reading data[sizeof(struct usb_ctrlrequest)] inside the
conditional.  Use sizeof(*req_pkt) instead of sizeof(struct
usb_ctrlrequest) for consistency.

[ johan: use dev_err(); split signals declaration and initialisation ]

## Affected

- `Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 < fbe60fd2abc8a5561f39719a41ad9a01b5d8e567`
- `Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 < 94e5525697b9e91ddc4071129874120a50a4f342`
- `Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 < 6b8cf5422c7e96ed5b22a8368eff663f3f98b8ec`
- `Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 < 030e3a73d3c3aa67c44454649e984d6383cdb7d3`
- `Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 < 060db7d48af1e650643c8b8319111a9ea2ce4486`
- `Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 < 2ef5560387f2c0713cee975be2b24b281bd90f3e`
- `Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 < a72a13c83a652516a0e469d275b81d29a7429049`
- `Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 < d762aef4eba354066be21a5d88eb2066e282f4c9`
- `Linux >= 58cfe9113e485f7e04bd0eac4fc4251b330af501 < 885d802f544ca7bfa8f3984d94233cce715bb6b3`
- `Linux 2.6.12`

## Remediation

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