So, there is a Terrible work around.
Blit the texture from the camera to a rendertexture > convert it to Texture2D > GetPixels32 from this Texture2D

Does this work - Yes
Is it performant - Hell no!
Should you do it - how desperate are you?

var rdTexture = new RenderTexture(camTexture.width, camTexture.height, 0);
Graphics.Blit(camTexture, rdTexture);
texture2D = ToTexture2D(rdTexture);
var pixelData = texture2D.GetPixels32();

public Texture2D ToTexture2D(RenderTexture rTex)
{
Texture2D tex = new Texture2D(rTex.width, rTex.height, TextureFormat.RGB24, false);
var old_rt = RenderTexture.active;
RenderTexture.active = rTex;

tex.ReadPixels(new Rect(0, 0, rTex.width, rTex.height), 0, 0);
tex.Apply();

RenderTexture.active = old_rt;
return tex;
}

We have the same problem in our 2023.2.2 WebGL project.
We need webCamTexture GetPixels32() as soon as possible.
Thank you

I have the same issue, which blocked my project.

Using Unity version 2021.3.32f1 can solve this issue, while versions 2022 and 2023 both result in black pixels.

I'm having this issue on WebGL, I've tried everything to get around this issue, even tried to bypass the GetPixels32 with this code which works on editor:

var tex2D = new Texture2D(webCamTexture.width, webCamTexture.height, TextureFormat.ARGB32, false);

Graphics.CopyTexture(RawImage.texture, tex2D);

but it seems that its broken entirely, it still only returns black pixels and you'll probably only be able to get the image if you make your own Javascript plugin.

This issue is very critical in the app I am currently creating and I hope it will be fixed ASAP.
https://forum.unity.com/threads/webcamtexture-returns-black-texture-on-android-browsers-and-webgl.1402138/