CVE-2021-4194Network attack vector

Unauthorized content moves via unchecked sort permissions

Published Jan 6, 2022 · Updated Aug 3, 2024

Improper access control in BookStack before 21.12.1 allows remote authenticated users to move pages or chapters to unauthorized locations. The book-sort and chapter-move paths apply attacker-supplied destination and ordering changes without verifying update, create, and delete permissions on every source item and parent. Any signed-in user who can reach the affected sorting operation can alter the location or order of content beyond that user's granted content permissions.

CVSS severity6.5
Medium
EPSS probability0.71%
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 21.12.1 allows remote authenticated users to move pages or chapters to unauthorized locations. The book-sort and chapter-move paths apply attacker-supplied destination and ordering changes without verifying update, create, and delete permissions on every source item and parent. Any signed-in user who can reach the affected sorting operation can alter the location or order of content beyond that user's granted content permissions.

The record

CVE
CVE-2021-4194
Published
Jan 6, 2022
Updated
Aug 3, 2024
Vendor
BookStack
Product
BookStack
Classifications
CWE-284, CWE-863, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 6, 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 <21.12.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

BookStack · BookStackversion=unspecified <21.12.1

Published CVSS scores

4.0NIST NVDAV:N/AC:L/Au:S/C:N/I:P/A:N
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
4.3huntr.devCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
CWE-863Incorrect Authorization
T1565.001Stored Data Manipulation

Public exploit references

No public exploit references are available in this record.

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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