CVE-2021-3986Network attack vector

Private shelf-name disclosure via unauthorized removal errors

Published Nov 15, 2024 · Updated Nov 15, 2024

Information disclosure in Calibre-Web before 0.6.15 allows remote authenticated users to read other users' private shelf names. The cps/shelf.py remove_from_shelf route interpolates shelf.name into its 403 response after rejecting removal from a shelf the requester does not own. Any authenticated account that can submit a removal request with another user's shelf identifier can learn that shelf's name, but cannot modify the shelf through this flaw.

CVSS severity4.3
Medium
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Calibre-Web before 0.6.15 allows remote authenticated users to read other users' private shelf names. The cps/shelf.py remove_from_shelf route interpolates shelf.name into its 403 response after rejecting removal from a shelf the requester does not own. Any authenticated account that can submit a removal request with another user's shelf identifier can learn that shelf's name, but cannot modify the shelf through this flaw.

The record

CVE
CVE-2021-3986
Published
Nov 15, 2024
Updated
Nov 15, 2024
Vendor
Calibre-Web
Product
Calibre-Web
Classifications
CWE-209
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?

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  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

4.3NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
4.3@huntr_aiCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/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.

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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-209Generation of Error Message Containing Sensitive Information

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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