CVE-2026-75871 — GitLab has remediated a vulnerability in the GitLab AI Gateway component affecting all…¶

Key facts

CVE-2026-75871 is a High (8.2) vulnerability: GitLab has remediated a vulnerability in the GitLab AI Gateway component affecting all…. This entry ships a detection-only PoC and a Docker test lab.


CVE	CVE-2026-75871
Severity	High (8.2)
Detection / prevention	—
PoC	poc.py
Source	2026/CVE-2026-75871/

Details¶

English | 한국어

Description¶

GitLab has remediated a vulnerability in the GitLab AI Gateway component affecting all versions of the AI Gateway from 18.10 to 19.0.12, 19.1 to 19.1.7, and 19.2 to 19.2.2 that could have allowed an authenticated user with Duo Agent Platform access to redirect outbound model requests to an externally-controlled endpoint via a crafted inline flow configuration that overrides the HTTP Host header, resulting in disclosure of Google Cloud Vertex cloud service credentials and private signing keys.

Vulnerability Details¶

Property	Value
CVE ID	CVE-2026-75871
Type	SSRF
CVSS Score	8.2

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-75871/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-2026-75871

# 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://gitlab.com/gitlab-org/gitlab/-/work_items/616990
https://hackerone.com/reports/3945100

Generated by PoC Generator on 2026-08-30T13:01:50.063127058

Frequently asked questions¶

What is CVE-2026-75871?¶

CVE-2026-75871 is a High (8.2) vulnerability: GitLab has remediated a vulnerability in the GitLab AI Gateway component affecting all…. This entry ships a detection-only PoC and a Docker test lab.

How do I detect CVE-2026-75871?¶

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-2026-75871?¶

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.