Nextcloud Talk is a video and audio conferencing app for Nextcloud. Prior to versions 12.2.7, 13.0.7, and 14.0.3, password protected conversations are susceptible to brute force attacks if the attacker has the link/conversation token. It is recommended that the Nextcloud Talk application is upgraded to 12.2.7, 13.0.7 or 14.0.3. There are currently no known workarounds available apart from not having password protected conversations.
https://hackerone.com/reports/1596673
https://github.com/nextcloud/spreed/pull/7537
https://github.com/nextcloud/spreed/pull/7536
https://github.com/nextcloud/spreed/pull/7535
https://github.com/nextcloud/spreed/pull/7504
https://github.com/nextcloud/spreed/commit/f5ac73940f9f683b11e518d1c54150bf50dab9be
https://github.com/nextcloud/spreed/commit/10341b9fe59a44ae0d139c072abd6b5026f33771
https://github.com/nextcloud/spreed/commit/04300bbed0e87ff3420b5d752bbc48e2c15f35e9
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-pf36-jvpv-4hwq