What is the bug or the crash?

Steps to reproduce the issue

• Load the world map
• Create a virtual layer using something like:

select fid, "NAME", transform(geometry,'EPSG:4326','EPSG:3857') geom from map where "NAME" in ('Zimbabwe','South Africa','Zambia','Malawi')

• Run the buffer algorithm from gdal
• see the error above

Versions

QGIS 3.40 Mac

Supported QGIS version

• I'm running a supported QGIS version according to the roadmap.

New profile

• I tried with a new QGIS profile

Additional context

Looking at the error message it seems the problem can be fixed by changing https://github.com/qgis/QGIS/blob/master/python/plugins/processing/algs/gdal/GdalUtils.py#L526-L529 to

from urllib.parse import unquote
elif 'layername' in uri:
      regex = re.compile(r'(?<=layername=)[^:|&]+')
      r = regex.search(unquote(uri))
      return r.groups(0)