# CVE-2026-41259

> Vulnerability · severity: **HIGH** (CVSS 7.5).

## Description

Mastodon is a free, open-source social network server based on ActivityPub. Prior to v4.5.9, v4.4.16, and v4.3.22, Mastodon allows restricting new user sign-up based on e-mail domain names, and performs basic validation on e-mail addresses, but fails to restrict characters that are interpreted differently by some mailing servers. This vulnerability is fixed in v4.5.9, v4.4.16, and v4.3.22.

## Key facts

- **CVE ID:** CVE-2026-41259
- **Published:** 2026-04-23
- **CVSS severity:** HIGH
- **CVSS base score:** 7.5
- **CWE codes:** CWE-841

## Affected products

- `joinmastodon:mastodon`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-41259

## Citation

> AI Analytics. CVE-2026-41259. Retrieved 2026-07-16 from https://api.ai-analytics.org/cve/CVE-2026-41259. Derived from NIST NVD. Licensed CC0.

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