1977739 - Firefox crashes consistently when trying to access the webcam on Windows 11 24H2 (Build 26120) — in release 141.0.2, Nightly, and even with all sandboxes disabled and using a clean profile.

Status: RESOLVED DUPLICATE of bug 1986922

(Core :: WebRTC, defect)

Description

[Milan]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/138.0.0.0 Safari/537.36

Steps to reproduce:

Launch Firefox (Release or Nightly)

Navigate to a webcam test site (e.g., https://webcamtests.com)

Allow camera access

Firefox crashes instantly

Actual results:

Crash Signature:
[@ RtlLookupFunctionEntry | RtlDispatchException | KiUserExceptionDispatch ...]
Crash Reason: EXCEPTION_ACCESS_VIOLATION_WRITE at 0x000000c335300eb0
Crash ID: a61af563-b119-49ed-acb0-399e40250717

Reproducibility: 100%
Other browsers (Chrome, Edge): Do not crash
Hardware: AMD CPU (family 26, model 68), 16 cores
OS: Windows 11 24H2 (10.0.26120)

What I’ve Tried:

Safe Mode

Clean test profile with user.js

Disabling RTSSHooks64.dll, NahimicOSD.dll, eOppBrowser.dll

--disable-untrusted-modules-scanner

Set all media-related prefs (VP8, sandbox, etc.)

Ran Firefox with:

powershell
Copy
Edit
$env:MOZ_DISABLE_CONTENT_SANDBOX = "1"
$env:MOZ_DISABLE_RDD_SANDBOX = "1"
$env:MOZ_DISABLE_GPU_SANDBOX = "1"
Start-Process "C:\Program Files\Mozilla Firefox\firefox.exe" -ArgumentList "--no-remote", "--profile", "$env:TEMP\FFCamTestProfile"
Tried Firefox Nightly — same crash

Suspected Component:
UntrustedModulesProcessor.cpp or MediaFoundation camera init inside xul.dll / mozglue.dll

Note:
This seems to occur before any logging or telemetry can be recorded. No MOZ_LOG output is generated.

Expected results:

Webcam opens normally

Comment 1

[Ardelean Oana, Desktop Test Engineering [:oardelean]]

Hello, thank you for the bug report!

I tried using the commands provided but no crash occurred. Tested on Windows 11(23H2) and Ubuntu 22.
Are there any other configurations, steps or environment variables needed to be set in order to reproduce the crash?

Moving the Component to ‘General’. Please change if there’s a better fit, thank you.

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Firefox for Android::General' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 3

[Milan]

Bug persists in Firefox 141 as well

Comment 4

[Milan]

Webcam that I own is Logitech C920. Windows 11 24H2 26120.5733

Comment 5

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:jimm, could you have a look please?

For more information, please visit BugBot documentation.

Comment 6

[JN]

I can confirm that a colleague and I have this exact same problem. Firefox crashes 100% each time an external (USB) webcam is accessed.
Even before video is send, for instance on the Google Meet "pre-meeting" page before clicking on join (but maybe it's because by default it tries to access the camera ?).
I'm on Windows 10, not sure on his side and can ask if it may help.
This is quite severe as it means we cannot work with Firefox anymore and have to switch to another browser (remote work with meetings).

This problem does not happen with a built-in webcam in a laptop.

Comment 7

[JN]

Additional details:
Hardware: AMD CPU (AMD Ryzen 7 4800H), 16 cores
OS: Windows 10 19045 (10.0.19045)
Webcam : Logitech HD Pro Webcam C920

Comment 8

[Trevor H]

I confirm I have this issue on 143.0.1. Any attempt to access the USB webcam with Firefox causes it to crash.

On webcamtests.com the camera seems detected and when you authorize it to identify the camera is when it crashes. Chrome works fine and I've had to switch browsers as a result of this bug.

Comment 9

[Trevor H]

Additional details:
Hardware: AMD CPU Ryzen 9 5900x
OS: Windows 11 24H2 26100.6584
Webcam : Logitech HD Pro Webcam C920
GPU: Nvidia 3080ti

Comment 10

[Alastor Wu [:alwu]]

Jan-Ivar, Andreas,
Do you have any thought about the crash caused by accessing a webcam? Thanks!

Comment 11

[Andreas Pehrson [:pehrsons] (PTO; back in Jan)]

Updating crash signature based on the provided crash id. I see a Quest 3 dll in a report. Do you and your colleague have Meta's Quest Link App installed?

Comment 12

[Andreas Pehrson [:pehrsons] (PTO; back in Jan)]

Having looked at a couple more crash reports matching this signature, the prevalence of magicdsfilterQuest3.dll suggests a yes to my question in comment 11. Same root cause as bug 1986922.