CVE-2021-4119Public exploitNetwork attack vector

User-detail disclosure via unprotected search endpoint

Published Dec 15, 2021 · Updated Aug 3, 2024

Improper access control in BookStack before 21.11.3 allows remote attackers to disclose user names and email addresses through user search. The UserSearchController user-select endpoint accepts unauthenticated queries and matches attacker-controlled search text against stored names and email addresses. No authentication or user interaction is required, and disclosure is limited to account details returned by matching queries.

CVSS severity5.3
Medium
EPSS probability26.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in BookStack before 21.11.3 allows remote attackers to disclose user names and email addresses through user search. The UserSearchController user-select endpoint accepts unauthenticated queries and matches attacker-controlled search text against stored names and email addresses. No authentication or user interaction is required, and disclosure is limited to account details returned by matching queries.

The record

CVE
CVE-2021-4119
Published
Dec 15, 2021
Updated
Aug 3, 2024
Vendor
BookStack
Product
BookStack
Classifications
CWE-284, T1087
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 15, 2021CVE 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 <21.11.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

BookStack · BookStackversion=unspecified <21.11.3

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
5.3huntr.devCVSS:3.0/AV:N/AC:L/PR:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-284Improper Access Control
T1087Account Discovery

Public exploit references

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Technologies

Your stack

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Your stack

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