CVE-2021-43820
7.4 · HIGHOverview
CVE-2021-43820 is a high-severity vulnerability affecting seafile seafile_server. It was published on December 14, 2021 and has a CVSS 3.1 base score of 7.4 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.4, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical 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.
Remediation
Check the references section for vendor advisories and patches from seafile. Update seafile_server to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| seafile | seafile_server | >= 0, < 8.0.8 | Affected |
Frequently Asked Questions
What is CVE-2021-43820?
CVE-2021-43820 is a high-severity vulnerability affecting seafile seafile_server. It was published on December 14, 2021 and has a CVSS 3.1 base score of 7.4 (HIGH).
How severe is CVE-2021-43820?
This vulnerability has a CVSS 3.1 base score of 7.4, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2021-43820?
Check the references section for vendor advisories and patches from seafile. Update seafile_server to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-43820?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-43820 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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