---
cve: "CVE-2026-41259"
severity: "HIGH"
cvss: 8.2
epss: "21%"
vendor: "mastodon"
kev: false
exploited: false
published: "2026-04-23 19:17:30"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-14T01:39:50+02:00"
---

# CVE-2026-41259

> 8.2 HIGH · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- 128393e2b4be5e7472fe4d59edd63d7b927831e5 (Commit)
- 7cbce428fd9f7b34f3d879417f0722f131e9d01f (Commit)

## Referenzen

- <https://github.com/mastodon/mastodon/security/advisories/GHSA-5r37-qpwq-2jhh>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-41259) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_