CVE-2021-4171Network attack vector

Duplicate public shelves via premature visibility update

Published Jan 17, 2022 · Updated Aug 3, 2024

Business logic error in Calibre-Web before 0.6.15 allows remote authenticated users to create duplicate public shelf names. The create_edit_shelf function updates shelf.is_public before check_shelf_is_unique validates the requested visibility and name. An account with public-shelf editing rights can corrupt the shared shelf namespace by changing a shelf's visibility to reuse an existing public name.

CVSS severity9.8
Critical
EPSS probability1.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Business logic error in Calibre-Web before 0.6.15 allows remote authenticated users to create duplicate public shelf names. The create_edit_shelf function updates shelf.is_public before check_shelf_is_unique validates the requested visibility and name. An account with public-shelf editing rights can corrupt the shared shelf namespace by changing a shelf's visibility to reuse an existing public name.

The record

CVE
CVE-2021-4171
Published
Jan 17, 2022
Updated
Aug 3, 2024
Vendor
Calibre-Web
Product
Calibre-Web
Classifications
CWE-840
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 17, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=unspecified <0.6.15

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Calibre-Web · Calibre-Webversion=unspecified <0.6.15

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.7huntr.devCVSS:3.0/AV:N/AC:H/PR:H/UI:N/S:C/C:N/I:H/A:H

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.

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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 exploitUnconfirmed

Weakness, pattern, technique

CWE-840Business Logic Errors

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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