CVE-2021-3986

Name: CVE-2021-3986
Creator: NVD / NIST
Published: 2024-11-15T11:15:06.4+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.3/10EPSS 0.36%

Last modified Jun 17, 2026

CVE-2021-3986 is a medium-severity vulnerability rated 4.3/10 on the CVSS scale. 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. EPSS estimates a 0.36% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

4.3/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

EPSS Probability

0.36%

27.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-209

Affected Software

Vendor	Product	Versions
Janeczku	Calibre-Web	< 0.6.15

References

https://github.com/janeczku/calibre-web/commit/6f5390ead5df9779ac81fadefffb476e03f93548Patch
https://huntr.com/bounties/394af194-61a7-4e33-b373-877d4c766fcaExploit, Issue Tracking, Patch, Third Party Advisory

Timeline

Published: Nov 15, 2024
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2021-3986?

How severe is CVE-2021-3986?

CVE-2021-3986 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 0.36% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3986?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3986?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST