---
cve: "CVE-2026-70617"
severity: "HIGH"
cvss: 8.6
epss: "23%"
vendor: "Spacebar Server"
kev: false
exploited: false
published: "2026-08-05 20:17:17"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-19T17:28:28+02:00"
---

# CVE-2026-70617

> 8.6 HIGH · 🧪 PoC

## Beschreibung

Spacebar Server before commit dcfd910 contains a missing authorization vulnerability that allows any authenticated attacker to add themselves to arbitrary group DM channels by sending a PUT request to the channels recipient endpoint without membership verification. Attackers can exploit the unguarded PUT /channels/{channel_id}/recipients/{user_id} handler to join private group DMs, read complete message history, post messages as a participant, and force-add third-party users without their consent.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- dcfd91035e3da42abf5f32d8d86a35219225b3d4 (Commit)

## Referenzen

- <https://github.com/spacebarchat/server/security/advisories/GHSA-g38j-78fh-jm74>
- <https://github.com/spacebarchat/server/commit/dcfd91035e3da42abf5f32d8d86a35219225b3d4>
- <https://www.vulncheck.com/advisories/spacebar-server-missing-authorization-via-group-dm-recipient-endpoint>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-70617) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_