An email address enumeration vulnerability exists in the password reset function of Rocket.Chat through 3.9.1.
https://trovent.io/security-advisory-2010-01
https://trovent.github.io/security-advisories/TRSA-2010-01/TRSA-2010-01.txt
http://www.openwall.com/lists/oss-security/2021/01/13/1
http://www.openwall.com/lists/oss-security/2021/01/08/1
http://www.openwall.com/lists/oss-security/2021/01/07/1
http://seclists.org/fulldisclosure/2021/Jan/43
http://seclists.org/fulldisclosure/2021/Jan/32
http://packetstormsecurity.com/files/160845/Rocket.Chat-3.7.1-Email-Address-Enumeration.html