CVE-2021-43820

Permissions check bypass in Seafile

Description

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.

Category

7.4
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.29%
Third-Party Advisory github.com Third-Party Advisory github.com
Affected: haiwen seafile-server
Published at:
Updated at:

References

Link Tags
https://github.com/haiwen/seafile-server/security/advisories/GHSA-m3wc-jv6r-hvv8 third party advisory
https://github.com/haiwen/seafile-server/pull/520 third party advisory patch

Frequently Asked Questions

What is the severity of CVE-2021-43820?
CVE-2021-43820 has been scored as a high severity vulnerability.
How to fix CVE-2021-43820?
To fix CVE-2021-43820, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-43820 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-43820 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-43820?
CVE-2021-43820 affects haiwen seafile-server.
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