CVE-2021-3987Public exploitNetwork attack vector

Unauthorized public-shelf creation via missing role check

Published Nov 15, 2024 · Updated Nov 15, 2024

Missing authorization in Calibre-Web before 0.6.15 allows remote authenticated users to create unauthorized public shelves. The create_shelf function in cps/shelf.py accepts POST requests without checking role_edit_shelfs before passing the new shelf to create_edit_shelf. Any logged-in account lacking the public-shelf editing right can publish a shelf, altering shared catalog state without that permission.

CVSS severity4.3
Medium
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in Calibre-Web before 0.6.15 allows remote authenticated users to create unauthorized public shelves. The create_shelf function in cps/shelf.py accepts POST requests without checking role_edit_shelfs before passing the new shelf to create_edit_shelf. Any logged-in account lacking the public-shelf editing right can publish a shelf, altering shared catalog state without that permission.

The record

CVE
CVE-2021-3987
Published
Nov 15, 2024
Updated
Nov 15, 2024
Vendor
Calibre-Web
Product
Calibre-Web
Classifications
CWE-284, CWE-862, T1565
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 15, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 15, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <*
  2. Affected versionversion=unspecified <=latest

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Calibre-Web · Calibre-Webversion=0 <*; version=unspecified <=latest

Published CVSS scores

4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
5.4huntr.devCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-284Improper Access Control
CWE-862Missing Authorization
T1565Data Manipulation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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