# CVE-2023-42450: Mastodon Server-Side Request Forgery vulnerability

> Attackers can inject data into HTTP requests to access local services if private addresses are allowed, requiring a patch.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Sep 2023
- **Updated:** 18 Jun 2025
- **Also known as:** BIT-mastodon-2023-42450, GHSA-hcqf-fw2r-52g4

## What is CVE-2023-42450?

CVE-2023-42450 is a medium-severity server-side request forgery vulnerability in mastodon, published on 19 Sep 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Mastodon is a free, open-source social network server based on ActivityPub. Starting in version 4.2.0-beta1 and prior to version 4.2.0-rc2, by crafting specific input, attackers can inject arbitrary data into HTTP requests issued by Mastodon. This can be used to perform confused deputy attacks if the server configuration includes `ALLOWED_PRIVATE_ADDRESSES` to allow access to local exploitable services. Version 4.2.0-rc2 has a patch for the issue.

Weakness: CWE-918 (Server-Side Request Forgery), CWE-113 (Improper Neutralization of CRLF Sequences in HTTP Headers)

## Which versions are affected by CVE-2023-42450?

1 open source package ship an affected version, including mastodon. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mastodon` | Bitnami | From 4.2.0-beta1 | 4.2.0, 4.2.0, 4.2.0, 4.2.0 |

Products: Joinmastodon Mastodon.

## How do I fix CVE-2023-42450?

Upgrade mastodon to 4.2.0 or later.

## Is CVE-2023-42450 being exploited?

There is no known exploitation of CVE-2023-42450 in the wild and no public exploit code.

## Other vulnerabilities in mastodon

- [CVE-2023-36460](https://insights.sbomify.com/CVE-2023-36460/): Mastodon vulnerable to arbitrary file creation through media attachments (critical 10.0)
- [CVE-2022-2166](https://insights.sbomify.com/CVE-2022-2166/): Improper Restriction of Excessive Authentication Attempts in mastodon/mastodon (critical 9.8)
- [CVE-2022-24307](https://insights.sbomify.com/CVE-2022-24307/): Missing authorization in n/a (critical 9.8)
- [CVE-2018-21018](https://insights.sbomify.com/CVE-2018-21018/): Auth bypass in n/a (critical 9.8)
- [CVE-2024-23832](https://insights.sbomify.com/CVE-2024-23832/): Mastodon Remote user impersonation and takeover (critical 9.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-42450 and fix it if it is affected.

What it is: CVE-2023-42450 is a medium-severity server-side request forgery vulnerability in mastodon, published on 19 Sep 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-42450 in the wild and no public exploit code.

Affected packages and fixed versions:
- mastodon (Bitnami): affected from 4.2.0-beta1; fixed in 4.2.0, 4.2.0, 4.2.0, 4.2.0

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-2023-42450/ (Markdown: https://insights.sbomify.com/CVE-2023-42450/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-42450
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-42450
- OSV: https://osv.dev/vulnerability/CVE-2023-42450

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-42450/
Summaries are generated and may contain mistakes; the official description above is the record.