CVE-2026-70617 — Spacebar Server before commit dcfd910 contains a missing authorization vulnerability that…¶

Key facts

CVE-2026-70617 is a High (8.1) vulnerability: Spacebar Server before commit dcfd910 contains a missing authorization vulnerability that…. This entry ships a detection-only PoC and a Docker test lab.


CVE	CVE-2026-70617
Severity	High (8.1)
Detection / prevention	—
PoC	poc.py
Source	2026/CVE-2026-70617/

Details¶

English | 한국어

Description¶

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.

Vulnerability Details¶

Property	Value
CVE ID	CVE-2026-70617
Type	RCE
CVSS Score	8.1

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-70617/poc.py

Usage¶

# Run PoC against target
python3 poc.py --target <TARGET_URL>

# With authentication
python3 poc.py --target <TARGET_URL> --username <USER> --password <PASS>

⚠️ Warning: This PoC is for authorized security testing only. It uses detection-only techniques and does not exploit or damage target systems.

Test Lab¶

This repository includes a Docker-based test environment with both vulnerable and patched applications.

Quick Start¶

# Clone and navigate to CVE directory
cd CVE-2026-70617

# Start both applications
docker-compose up -d

# Run tests
./run-tests.sh    # Linux/Mac
./run-tests.ps1   # Windows PowerShell

Application Endpoints¶

Application	URL	Status
Vulnerable App	http://localhost:8080	Shows vulnerability
Patched App	http://localhost:8081	Demonstrates fix

Directory Structure¶

├── README.md           # English documentation
├── README_KO.md        # Korean documentation
├── poc.py              # PoC detection script
├── docker-compose.yml  # Container orchestration
├── run-tests.sh        # Linux/Mac test runner
├── run-tests.ps1       # Windows test runner
├── vulnerable-app/     # Vulnerable version
│   ├── app.py
│   ├── Dockerfile
│   └── requirements.txt
└── patched-app/        # Fixed version
    ├── app.py
    ├── Dockerfile
    └── requirements.txt

References¶

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

Generated by PoC Generator on 2026-08-09T02:53:44.834873427

Frequently asked questions¶

What is CVE-2026-70617?¶

CVE-2026-70617 is a High (8.1) vulnerability: Spacebar Server before commit dcfd910 contains a missing authorization vulnerability that…. This entry ships a detection-only PoC and a Docker test lab.

How do I detect CVE-2026-70617?¶

Run the detection-only PoC included with this entry against your Docker test lab to confirm whether a target is affected; pair it with your own IDS logging.

How do I block or mitigate CVE-2026-70617?¶

Upgrade to a fixed version per the vendor advisory; the NVD record lists the affected versions. Use the included PoC to verify your remediation.

For authorized security testing and research only. See the full source and NVD record.