CVE-2026-53513 — Better Auth is an authentication and authorization library for TypeScript.¶
Key facts
CVE-2026-53513 is a Critical (9.6) vulnerability: Better Auth is an authentication and authorization library for TypeScript.. This entry ships a detection-only PoC and a Docker test lab.
| CVE | CVE-2026-53513 |
| Severity | Critical (9.6) |
| Detection / prevention | — |
| PoC | poc.py |
| Source | 2026/CVE-2026-53513/ |
Details¶
English | 한국어
Description¶
Better Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, the @better-auth/sso plugin's POST /sso/register and POST /sso/update-provider endpoints accept attacker-controlled oidcConfig.userInfoEndpoint, tokenEndpoint, and jwksEndpoint URLs when skipDiscovery: true is set, store them on the ssoProvider row without origin validation, and fetch them during OIDC callback, allowing non-blind server-side request forgery and possible account linking when trustEmailVerified: true is configured. This issue is fixed in version 1.6.11.
Vulnerability Details¶
| Property | Value |
|---|---|
| CVE ID | CVE-2026-53513 |
| Type | SSRF |
| CVSS Score | 9.6 |
Proof of Concept¶
Download¶
# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-53513/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-2026-53513
# 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/better-auth/better-auth/commit/37f60cb176cb53147da7dfd5ec15afa5b486e81e
- https://github.com/better-auth/better-auth/pull/9574
- https://github.com/better-auth/better-auth/releases/tag/v1.6.11
- https://github.com/better-auth/better-auth/security/advisories/GHSA-5rr4-8452-hf4v
Generated by PoC Generator on 2026-07-16T05:19:51.120720669
Frequently asked questions¶
What is CVE-2026-53513?¶
CVE-2026-53513 is a Critical (9.6) vulnerability: Better Auth is an authentication and authorization library for TypeScript.. This entry ships a detection-only PoC and a Docker test lab.
How do I detect CVE-2026-53513?¶
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-2026-53513?¶
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.