# CVE-2020-26260: Server Side Request Forgery in BookStack

> An attacker with page edit permissions can trigger server-side requests and access internal files via manipulated image URLs in BookStack.

- **Severity:** Medium 6.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Dec 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-8wfc-w2r5-x7cr

## What is CVE-2020-26260?

CVE-2020-26260 is a medium-severity server-side request forgery vulnerability in BookStackApp BookStack, published on 9 Dec 2020. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

BookStack is a platform for storing and organising information and documentation. In BookStack before version 0.30.5, a user with permissions to edit a page could set certain image URL's to manipulate functionality in the exporting system, which would allow them to make server side requests and/or have access to a wider scope of files within the BookStack file storage locations. The issue was addressed in BookStack v0.30.5. As a workaround, page edit permissions could be limited to only those that are trusted until you can upgrade.

Weakness: CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component)

## Which versions are affected by CVE-2020-26260?

It affects 1 product.


Products: Bookstackapp Bookstack.

## How do I fix CVE-2020-26260?

No fix has been published for CVE-2020-26260 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-26260 being exploited?

There is no known exploitation of CVE-2020-26260 in the wild and no public exploit code.

## Other vulnerabilities in BookStackApp BookStack

- [CVE-2020-5256](https://insights.sbomify.com/CVE-2020-5256/): Remote Code Execution Through Image Uploads in BookStack (high 7.9)
- [CVE-2020-26210](https://insights.sbomify.com/CVE-2020-26210/): Cross-Site Scripting in BookStack (high 7.7)
- [CVE-2020-26211](https://insights.sbomify.com/CVE-2020-26211/): Cross-Site Scripting in BookStack (high 7.7)
- [CVE-2022-0877](https://insights.sbomify.com/CVE-2022-0877/): Cross-site Scripting (XSS) - Stored in bookstackapp/bookstack (high 7.6)
- [CVE-2021-3915](https://insights.sbomify.com/CVE-2021-3915/): Unrestricted Upload of File with Dangerous Type in bookstackapp/bookstack (high 7.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-26260 and fix it if it is affected.

What it is: CVE-2020-26260 is a medium-severity server-side request forgery vulnerability in BookStackApp BookStack, published on 9 Dec 2020. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-26260 in the wild and no public exploit code.

Affected product: BookStackApp BookStack. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2020-26260/ (Markdown: https://insights.sbomify.com/CVE-2020-26260/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-26260
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-26260
- OSV: https://osv.dev/vulnerability/CVE-2020-26260

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-26260/
Summaries are generated and may contain mistakes; the official description above is the record.