CVE-2026-49457 — erlang_quic is a pure Erlang QUIC implementation.¶

Key facts

CVE-2026-49457 is a Critical (9.1) vulnerability: erlang_quic is a pure Erlang QUIC implementation.. This entry ships a detection-only PoC and a Docker test lab.


CVE	CVE-2026-49457
Severity	Critical (9.1)
Detection / prevention	—
PoC	poc.py
Source	2026/CVE-2026-49457/

Details¶

English | 한국어

Description¶

erlang_quic is a pure Erlang QUIC implementation. Prior to version 1.4.4, the QUIC client did not authenticate the server during the TLS 1.3 handshake. The CertificateVerify signature was not checked, the certificate chain was not validated, and the hostname was not compared against the certificate, so verify was effectively a no-op on the client. A man-in-the-middle on the network path could present any certificate and impersonate any server, defeating the confidentiality and integrity of the connection. HTTP/3 uses the same client and was equally affected. Handshakes authenticated by a PSK (session resumption) are not affected, because the peer is authenticated by the PSK binder and no certificate is sent. This is fixed in 1.4.4. The client now verifies the CertificateVerify signature, validates the certificate chain against the trust store (cacerts option, the operating system store by default), and checks the hostname. Client verify now defaults to on; set verify => false to accept any certificate (for example a self-signed test server). No known workarounds are available before 1.4.4. verify => true had no effect, and inspecting the certificate after connecting does not help because without the signature check the peer is never proven to own the certificate it presents.

Vulnerability Details¶

Property	Value
CVE ID	CVE-2026-49457
CVSS Score	9.1

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-49457/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-2026-49457

# 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/benoitc/erlang_quic/security/advisories/GHSA-2r8v-p65x-3663

Generated by PoC Generator on 2026-08-15T05:52:04.319580745

Frequently asked questions¶

What is CVE-2026-49457?¶

CVE-2026-49457 is a Critical (9.1) vulnerability: erlang_quic is a pure Erlang QUIC implementation.. This entry ships a detection-only PoC and a Docker test lab.

How do I detect CVE-2026-49457?¶

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-2026-49457?¶

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.