# CVE-2023-36462: Mastodon's verified profile links can be formatted in a misleading way

> Attackers can craft misleading verified profile links to facilitate phishing attacks by concealing the true destination URL.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 6 Jul 2023
- **Updated:** 24 Oct 2024
- **Also known as:** BIT-mastodon-2023-36462, GHSA-55j9-c3mp-6fcq

## What is CVE-2023-36462?

CVE-2023-36462 is a medium-severity vulnerability in mastodon, published on 6 Jul 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Mastodon is a free, open-source social network server based on ActivityPub. Starting in version 2.6.0 and prior to versions 3.5.9, 4.0.5, and 4.1.3, an attacker can craft a verified profile link using specific formatting to conceal arbitrary parts of the link, enabling it to appear to link to a different URL altogether. The link is visually misleading, but clicking on it will reveal the actual link. This can still be used for phishing, though, similar to IDN homograph attacks. Versions 3.5.9, 4.0.5, and 4.1.3 contain a patch for this issue.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2023-36462?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mastodon` | Bitnami | From 2.6.0 | 3.5.9, 4.0.5, 4.1.3 |

Products: Joinmastodon Mastodon.

## How do I fix CVE-2023-36462?

Upgrade mastodon to a fixed version for your release line: 3.5.9, 4.0.5 or 4.1.3.

## Is CVE-2023-36462 being exploited?

There is no known exploitation of CVE-2023-36462 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-2023-36462 and fix it if it is affected.

What it is: CVE-2023-36462 is a medium-severity vulnerability in mastodon, published on 6 Jul 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2023-36462 in the wild and no public exploit code.

Affected packages and fixed versions:
- mastodon (Bitnami): affected from 2.6.0; fixed in 3.5.9, 4.0.5, 4.1.3

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-2023-36462/ (Markdown: https://insights.sbomify.com/CVE-2023-36462/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-36462
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-36462
- OSV: https://osv.dev/vulnerability/CVE-2023-36462

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-36462/
Summaries are generated and may contain mistakes; the official description above is the record.