---
id: CVE-2026-68217
title: 'media: pwc: Drain fill_buf on start_streaming() failure'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  media: pwc: Drain fill_buf on start_streaming() failure

  pwc_isoc_init() submits its isochronous URBs with
  usb_submit_urb(.., GFP_KERNEL) in a loop. After the first URB…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 885fe18f5542fe283a17f70583383c6cadcba1c3 <
    97f3c15957ec7e6d249f05407ad947c0644df24d
  - >-
    Linux >= 885fe18f5542fe283a17f70583383c6cadcba1c3 <
    a4afffd148991a826e8995362fb10cf8705c1130
  - >-
    Linux >= 885fe18f5542fe283a17f70583383c6cadcba1c3 <
    eabe9a59640698137d7382d5b549e95dc37f7565
  - >-
    Linux >= 885fe18f5542fe283a17f70583383c6cadcba1c3 <
    a56e7641e09bd80b976e944ae759109b86fd5b38
  - >-
    Linux >= 885fe18f5542fe283a17f70583383c6cadcba1c3 <
    acc789b2173070638cad89c2b61d33ed338be0dd
  - >-
    Linux >= 885fe18f5542fe283a17f70583383c6cadcba1c3 <
    9afd605dcd96c7a45f338eded1de16679b30e1df
  - >-
    Linux >= 885fe18f5542fe283a17f70583383c6cadcba1c3 <
    5d4812668b03f823b5044789d6aa77fe56b42587
  - >-
    Linux >= 885fe18f5542fe283a17f70583383c6cadcba1c3 <
    906e410dcffbbd99fb4081abab817a830033aa28
  - Linux 3.1
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T16:44:48.652931Z'
published: '2026-08-10'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T16:55:09.601Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-68217'
references:
  - url: 'https://git.kernel.org/stable/c/97f3c15957ec7e6d249f05407ad947c0644df24d'
  - url: 'https://git.kernel.org/stable/c/a4afffd148991a826e8995362fb10cf8705c1130'
  - url: 'https://git.kernel.org/stable/c/eabe9a59640698137d7382d5b549e95dc37f7565'
  - url: 'https://git.kernel.org/stable/c/a56e7641e09bd80b976e944ae759109b86fd5b38'
  - url: 'https://git.kernel.org/stable/c/acc789b2173070638cad89c2b61d33ed338be0dd'
  - url: 'https://git.kernel.org/stable/c/9afd605dcd96c7a45f338eded1de16679b30e1df'
  - url: 'https://git.kernel.org/stable/c/5d4812668b03f823b5044789d6aa77fe56b42587'
  - url: 'https://git.kernel.org/stable/c/906e410dcffbbd99fb4081abab817a830033aa28'
tags:
  - cve.org
epss: 0.0022
epssPercentile: 0.12607
ingestedAt: '2026-11-06T18:00:12.620Z'
---

## Overview

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

media: pwc: Drain fill_buf on start_streaming() failure

pwc_isoc_init() submits its isochronous URBs with
usb_submit_urb(.., GFP_KERNEL) in a loop. After the first URB is
submitted, its completion handler pwc_isoc_handler() can run on another
CPU before the loop finishes:

  start_streaming()
    pwc_isoc_init()
      usb_submit_urb(urbs[0], GFP_KERNEL)
                                  pwc_isoc_handler(urbs[0])
                                    pdev->fill_buf =
                                      pwc_get_next_fill_buf(pdev)
      usb_submit_urb(urbs[i>0], ..)  -> fails
      pwc_isoc_cleanup(pdev)           /* kills URBs */
      return ret;
    pwc_cleanup_queued_bufs(pdev, VB2_BUF_STATE_QUEUED)

pwc_get_next_fill_buf() detaches a buffer from pdev->queued_bufs and
stores it in pdev->fill_buf. The error path in start_streaming() only
drains pdev->queued_bufs, so the buffer parked in pdev->fill_buf is
leaked. vb2_start_streaming() then triggers
WARN_ON(owned_by_drv_count).

stop_streaming() already handles this since commit 80b0963e1698
("[media] pwc: fix WARN_ON"), which added the fill_buf drain in the
teardown path but not in the start_streaming() error path. Mirror that
handling on failure so start_streaming() returns with no buffer owned
by the driver.

Issue identified by automated review of the INV-003 series at
https://sashiko.dev/

## Affected

- `Linux >= 885fe18f5542fe283a17f70583383c6cadcba1c3 < 97f3c15957ec7e6d249f05407ad947c0644df24d`
- `Linux >= 885fe18f5542fe283a17f70583383c6cadcba1c3 < a4afffd148991a826e8995362fb10cf8705c1130`
- `Linux >= 885fe18f5542fe283a17f70583383c6cadcba1c3 < eabe9a59640698137d7382d5b549e95dc37f7565`
- `Linux >= 885fe18f5542fe283a17f70583383c6cadcba1c3 < a56e7641e09bd80b976e944ae759109b86fd5b38`
- `Linux >= 885fe18f5542fe283a17f70583383c6cadcba1c3 < acc789b2173070638cad89c2b61d33ed338be0dd`
- `Linux >= 885fe18f5542fe283a17f70583383c6cadcba1c3 < 9afd605dcd96c7a45f338eded1de16679b30e1df`
- `Linux >= 885fe18f5542fe283a17f70583383c6cadcba1c3 < 5d4812668b03f823b5044789d6aa77fe56b42587`
- `Linux >= 885fe18f5542fe283a17f70583383c6cadcba1c3 < 906e410dcffbbd99fb4081abab817a830033aa28`
- `Linux 3.1`

## Remediation

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