# CVE-2026-22246: Local Mastodon users can enumerate and access severed relationships of every other local user

> Local users can enumerate and access severed relationship lists of other users due to missing ownership checks, leaking private social graph data.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/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:** Yes
- **Published:** 8 Jan 2026
- **Updated:** 8 Jan 2026
- **Also known as:** BIT-mastodon-2026-22246, GHSA-ww85-x9cp-5v24

## What is CVE-2026-22246?

CVE-2026-22246 is a medium-severity vulnerability in mastodon, published on 8 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Mastodon is a free, open-source social network server based on ActivityPub. Mastodon 4.3 added notifications of severed relationships, allowing end-users to inspect the relationships they lost as the result of a moderation action. The code allowing users to download lists of severed relationships for a particular event fails to check the owner of the list before returning the lost relationships. Any registered local user can access the list of lost followers and followed users caused by any severance event, and go through all severance events this way. The leaked information does not include the name of the account which has lost follows and followers. This has been fixed in Mastodon v4.3.17, v4.4.11 and v4.5.4.

Weakness: CWE-201 (Insertion of Sensitive Information Into Sent Data)

## Which versions are affected by CVE-2026-22246?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mastodon` | Bitnami | All versions | 4.3.17, 4.4.11, 4.5.4 |

Products: Joinmastodon Mastodon.

## How do I fix CVE-2026-22246?

Upgrade mastodon to a fixed version for your release line: 4.3.17, 4.4.11 or 4.5.4.

## Is CVE-2026-22246 being exploited?

There is no known exploitation of CVE-2026-22246 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-2026-22246 and fix it if it is affected.

What it is: CVE-2026-22246 is a medium-severity vulnerability in mastodon, published on 8 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-22246 in the wild and no public exploit code.

Affected packages and fixed versions:
- mastodon (Bitnami): affected all versions; fixed in 4.3.17, 4.4.11, 4.5.4

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-2026-22246/ (Markdown: https://insights.sbomify.com/CVE-2026-22246/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-22246
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-22246
- OSV: https://osv.dev/vulnerability/CVE-2026-22246

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-22246/
Summaries are generated and may contain mistakes; the official description above is the record.