CVE-2021-43820

CVE-2021-43820 is a medium-severity vulnerability affecting Seafile and Seafile Server, an open-source cloud storage system. It allows an attacker with a valid sync token to access data from any known library, bypassing library-specific authorization checks due to improper token validation in the server's cache. The attack complexity is high, as the attacker must discover a library's random UUID, which is not guessable. There is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this vulnerability.