convert (imagemagick) hangs with some svg files on Ubuntu 20.04

[r0mulux]

$ convert /usr/share/icons/breeze/devices/16/input-mouse.svg output.png

-> command hangs and eats 100% of cpu.

$ which convert
/usr/bin/convert

$ file /usr/bin/convert
/usr/bin/convert: symbolic link to /etc/alternatives/convert

$ file /etc/alternatives/convert
/etc/alternatives/convert: symbolic link to /usr/bin/convert-im6.q16

$ file /usr/bin/convert-im6.q16
/usr/bin/convert-im6.q16: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=54d8d2c5f6ceae6ebadcf8f452bf544bcad0f150, for GNU/Linux 3.2.0, stripped

$ dpkg -S /usr/bin/convert-im6.q16
imagemagick-6.q16: /usr/bin/convert-im6.q16

$ dpkg -l imagemagick-6.q16
Souhait=inconnU/Installé/suppRimé/Purgé/H=à garder
| État=Non/Installé/fichier-Config/dépaqUeté/échec-conFig/H=semi-installé/W=attend-traitement-déclenchements
|/ Err?=(aucune)/besoin Réinstallation (État,Err: majuscule=mauvais)
||/ Nom Version Architecture Description
+++-=================-============================-============-================================================
ii imagemagick-6.q16 8:6.9.10.23+dfsg-2.1ubuntu11 amd64 image manipulation programs -- quantum depth Q16

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Phil Driscoll (phil-dialsolutions)]

Just a note for anyone running MediaWiki, where this problem causes pages to hang for several minutes until 'convert' times out. I worked around the problem by installing rsvg (apt install librsvg2-bin) and setting $wgSVGConverter = 'rsvg' in LocalSettings.php