CVE-2026-55872 — GYM One is open-source gym management software for fitness centers, personal trainers,…¶
Key facts
CVE-2026-55872 is a High (8.7) vulnerability: GYM One is open-source gym management software for fitness centers, personal trainers,…. This entry ships a detection-only PoC and a Docker test lab.
| CVE | CVE-2026-55872 |
| Severity | High (8.7) |
| Detection / prevention | — |
| PoC | poc.py |
| Source | 2026/CVE-2026-55872/ |
Details¶
English | 한국어
Description¶
GYM One is open-source gym management software for fitness centers, personal trainers, and sports clubs. Prior to 1.4.1, GYM One's admin/users/index.php renders the stored firstname, lastname, and email profile fields into the administrator user list without HTML output encoding. An attacker who can store values in those fields can cause content to execute in an administrator's browser when the administrator visits /admin/users/. The persistent script can access administrator-session data or perform actions with the administrator's privileges until the stored record is removed. This issue is fixed in version 1.4.1.
Vulnerability Details¶
| Property | Value |
|---|---|
| CVE ID | CVE-2026-55872 |
| Type | XSS |
| CVSS Score | 8.7 |
Proof of Concept¶
Download¶
# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-55872/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-2026-55872
# 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/mayerbalintdev/GYM-One/commit/d3a0cf134f0ab3ac12aee7dca283b93c4290dcc4
- https://github.com/mayerbalintdev/GYM-One/releases/tag/V1.4.1
- https://github.com/mayerbalintdev/GYM-One/security/advisories/GHSA-75g9-vp9w-5388
Generated by PoC Generator on 2026-10-16T06:28:08.07836038
Frequently asked questions¶
What is CVE-2026-55872?¶
CVE-2026-55872 is a High (8.7) vulnerability: GYM One is open-source gym management software for fitness centers, personal trainers,…. This entry ships a detection-only PoC and a Docker test lab.
How do I detect CVE-2026-55872?¶
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-2026-55872?¶
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.