CVE-2021-43820

MEDIUM
Published Dec 14, 20214y ago · Modified Jun 17, 20262w ago
5.9 CVSS 3.1
Medium
Find Similar
Published Dec 14, 2021 4y ago
Last Modified Jun 17, 2026 2w ago

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.

CVSS Details

Base Score
5.9
Exploitability
2.2
Impact
3.6
Vector string
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack Vector Network
Attack Complexity High
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality High
Integrity None
Availability None

Threat Intelligence

No active exploitation signals — not in CISA KEV and no EPSS score yet.

Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-639

Affected Products 3

VendorProductVersionRange
seafileseafile_server* <8.0.8
seafileseafile_server* <8.0.15
seafileseafile_server*≥9.0.0  –  <9.0.2

References 2

  • github.com https://github.com/haiwen/seafile-server/pull/520
    PatchThird Party Advisory
  • github.com https://github.com/haiwen/seafile-server/security/advisories/GHSA-m3wc-jv6r-hvv8
    Third Party Advisory

Remediation

  • github.com https://github.com/haiwen/seafile-server/pull/520
    PatchThird Party Advisory