# CVE-2021-4026: bookstack is vulnerable to Improper Access Control

Source: https://junglewise.ai/threats/cve-2021-4026-bookstack-is-vulnerable-to-improper-access-control  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2021-12-01  
License: CC BY 4.0 with a link back

CVE-2021-4026 · Severity: low · CVSS 3.1 · Published 2021-12-01

bookstack is vulnerable to Improper Access Control

Technologies: [ssddanbrown/bookstack (Packagist)](https://junglewise.ai/threats/technologies/ssddanbrown-bookstack). Vendors: [Packagist](https://junglewise.ai/threats/vendors/packagist).

## Quick answers

**Is CVE-2021-4026 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2021-4026 being exploited in the wild.

**How severe is CVE-2021-4026?** Low severity, with a CVSS score of 3.1, published 1 December 2021.

**Which products and versions are affected?** ssddanbrown/bookstack (Packagist) ECOSYSTEM:introduced=0,fixed=21.11.2.

**Is there a fix for CVE-2021-4026?** Yes. ssddanbrown/bookstack (Packagist): upgrade to 21.11.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2021-4026?** Check whether you run ssddanbrown/bookstack (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- ssddanbrown/bookstack (Packagist): upgrade to 21.11.2 or later

  ```sh
  composer require ssddanbrown/bookstack:^21.11.2
  ```


## Affected products

- ssddanbrown/bookstack (Packagist) ECOSYSTEM:introduced=0,fixed=21.11.2

## Identifiers

- CVE-2021-4026
- GHSA-jm6p-wfjg-xm7x

## Related threats

- [BookStack Incorrect Access Control vulnerability](https://junglewise.ai/threats/cve-2024-36676-bookstack-incorrect-access-control-vulnerability)
- [Bookstack Cross-site Scripting vulnerability](https://junglewise.ai/threats/cve-2020-26211-bookstack-cross-site-scripting-vulnerability)
- [Cross-site Scripting in BookStack](https://junglewise.ai/threats/cve-2022-0877-cross-site-scripting-in-bookstack)
- [bookstack is vulnerable to Improper Access Control](https://junglewise.ai/threats/cve-2021-4194-bookstack-is-vulnerable-to-improper-access-control)
- [BookStack is vulnerable to Improper Access Control.](https://junglewise.ai/threats/cve-2021-4119-bookstack-is-vulnerable-to-improper-access-control)