Is CVE-2021-3986 actively exploited?

No active exploitation of CVE-2021-3986 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-3986 be exploited remotely?

Yes. CVE-2021-3986 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-3986?

CVE-2021-3986 has a CVSS score of 4.3 (MEDIUM).

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MEDIUM

CVE-2021-3986

CWE-209Published: November 15, 2024· Updated: Jun 17, 2026

4.3

CVSS v3.1

Official Description

A vulnerability in janeczku/calibre-web allows unauthorized users to view the names of private shelves belonging to other users. This issue occurs in the file shelf.py at line 221, where the name of the shelf is exposed in an error message when a user attempts to remove a book from a shelf they do not own. This vulnerability discloses private information and affects all versions prior to the fix.

NVD Source

Technical Analysis

CVE-2021-3986 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.