CVE-2021-43820

Seafile is an open source cloud storage system. A sync token is used in
Seafile file syncing protocol to authorize access to library data. To
improve performance, the token is cached in memory in seaf-server. Upon
receiving a token from sync client or SeaDrive client, the server checks
whether the token exist in the cache. However, if the token exists in
cache, the server doesn’t check whether it’s associated with the specific
library in the URL. This vulnerability makes it possible to use any valid
sync token to access data from any known library. Note that the
attacker has to first find out the ID of a library which it has no access
to. The library ID is a random UUID, which is not possible to be guessed.
There are no workarounds for this issue.

Notes