CVE-2026-3193: Chia Blockchain CSRF Vulnerability

CVE-2026-3193 Overview

A Cross-Site Request Forgery (CSRF) vulnerability has been identified in Chia Blockchain version 2.1.0. The vulnerability affects the /send_transaction endpoint, allowing remote attackers to potentially manipulate transaction functionality through forged requests. While the attack requires high complexity and user interaction, the exploit has been made public, increasing the risk of exploitation in the wild.

Critical Impact

Remote attackers can potentially trigger unauthorized transaction operations by tricking authenticated users into visiting malicious pages, though exploitation requires high complexity.

Affected Products

• Chia Blockchain 2.1.0

Discovery Timeline

• 2026-02-25 - CVE CVE-2026-3193 published to NVD
• 2026-02-25 - Last updated in NVD database

Technical Details for CVE-2026-3193

Vulnerability Analysis

This vulnerability is classified as Cross-Site Request Forgery (CWE-352), where the /send_transaction endpoint lacks proper anti-CSRF protections. The attack can be launched remotely over the network but requires high complexity to execute successfully. User interaction is required, meaning an attacker must convince a victim with an active Chia Blockchain session to visit a malicious webpage or click a crafted link.

The vendor was notified early via email, and a separate bug bounty report was submitted. However, the vendor rejected the report stating "This is by design. The user is responsible for host security." This response indicates the vendor considers CSRF protection to be outside their security responsibility, placing the burden on users to secure their local environment.

Root Cause

The root cause of this vulnerability stems from insufficient CSRF token validation or the absence of anti-CSRF mechanisms in the /send_transaction function. Without proper state-changing request verification, the application cannot distinguish between legitimate user-initiated requests and forged requests from malicious third-party sites.

Attack Vector

The attack is network-based, requiring an attacker to craft a malicious webpage containing a forged request targeting the /send_transaction endpoint. When an authenticated Chia Blockchain user visits the attacker's page, their browser automatically includes session credentials with the forged request. Despite the high complexity and difficult exploitability, the public availability of exploit code increases the threat level.

The vulnerability mechanism involves an attacker embedding a hidden form or script on a malicious webpage that submits a transaction request to the victim's local Chia Blockchain instance. Technical details and proof-of-concept code are available in the GitHub PoC Repository.

Detection Methods for CVE-2026-3193

Indicators of Compromise

• Unexpected transaction submissions originating from user sessions during web browsing activity
• HTTP request logs showing /send_transaction requests with external referer headers
• Transaction logs indicating activity during times when users did not intentionally initiate transfers

Detection Strategies

• Monitor web server logs for /send_transaction requests with suspicious or external referer headers
• Implement network monitoring to detect cross-origin requests to the Chia Blockchain RPC interface
• Review transaction history for unauthorized or unexpected transfers that correlate with user browsing activity

Monitoring Recommendations

• Enable detailed logging for all RPC endpoint access, particularly /send_transaction
• Configure alerting for transaction requests that originate from unusual sources or contain unexpected parameters
• Implement browser-side monitoring for users accessing sensitive blockchain management interfaces

How to Mitigate CVE-2026-3193

Immediate Actions Required

• Restrict access to the Chia Blockchain RPC interface to trusted networks only
• Implement firewall rules to block external access to the /send_transaction endpoint
• Advise users to avoid browsing untrusted websites while authenticated to Chia Blockchain
• Consider using browser isolation or separate browser profiles for blockchain management

Patch Information

No official patch is currently available. The vendor has indicated that CSRF protection is considered outside the scope of their security model, stating that users are responsible for host security. Users should implement the workarounds described below and monitor VulDB for any updates.

Workarounds

• Configure local firewall rules to restrict RPC access to 127.0.0.1 only
• Use a reverse proxy with CSRF protection to front the Chia Blockchain RPC interface
• Implement network segmentation to isolate blockchain nodes from general browsing environments
• Enable SameSite cookie attributes if using custom authentication mechanisms

# Configuration example - Restrict RPC access with firewall rules
# Block external access to Chia RPC port (default 8555)
sudo iptables -A INPUT -p tcp --dport 8555 ! -s 127.0.0.1 -j DROP

# Alternatively, configure Chia to listen only on localhost
# Edit ~/.chia/mainnet/config/config.yaml
# Set self_hostname: 127.0.0.1 under wallet and full_node sections