CVE-2026-42518: e-Sushrut Information Disclosure Flaw

CVE-2026-42518 Overview

This vulnerability exists in e-Sushrut due to disclosure of sensitive information and hardcoded AES encryption keys in client-side JavaScript. An unauthenticated remote attacker could exploit this vulnerability by accessing the client-side code to extract sensitive information and cryptographic keys.

Successful exploitation of this vulnerability could lead to exposure of sensitive data and compromise of cryptographic protections on the targeted system. This is a classic example of CWE-321 (Use of Hard-coded Cryptographic Key), where encryption keys embedded in client-accessible code render the cryptographic protection ineffective.

Critical Impact

Unauthenticated attackers can extract hardcoded AES encryption keys from client-side JavaScript, potentially decrypting all protected data and compromising the cryptographic security of the entire system.

Affected Products

• e-Sushrut Healthcare Management System

Discovery Timeline

• 2026-04-29 - CVE CVE-2026-42518 published to NVD
• 2026-04-29 - Last updated in NVD database

Technical Details for CVE-2026-42518

Vulnerability Analysis

The vulnerability stems from improper handling of cryptographic keys within the e-Sushrut application. By embedding AES encryption keys directly in client-side JavaScript, the application exposes these secrets to anyone who can view the page source or inspect network traffic. This fundamentally violates cryptographic best practices, as the security of symmetric encryption relies entirely on the secrecy of the key.

The network-accessible nature of this vulnerability means that any unauthenticated remote user can simply browse to the application, open browser developer tools, and inspect the JavaScript source code to extract the hardcoded encryption keys. No special tools, privileges, or complex attack chains are required—the keys are effectively public.

Root Cause

The root cause is the use of hardcoded cryptographic keys (CWE-321) in client-side JavaScript. Developers embedded AES encryption keys directly in JavaScript source code that is delivered to users' browsers. This approach fails to recognize that client-side code is inherently accessible to end users and cannot be trusted to protect secrets. Proper key management requires server-side key storage, secure key derivation, or proper key exchange protocols.

Attack Vector

The attack vector for this vulnerability is network-based and requires no authentication. An attacker can exploit this vulnerability through the following approach:

1. Navigate to the e-Sushrut web application in any modern browser
2. Open browser developer tools (F12) or view page source
3. Inspect loaded JavaScript files or inline scripts
4. Search for AES key patterns, encryption initialization vectors, or crypto-related variable names
5. Extract the hardcoded encryption key and any associated cryptographic parameters
6. Use the extracted key to decrypt any data protected by the compromised encryption scheme

The extracted keys can then be used to decrypt sensitive healthcare information, forge encrypted tokens, or bypass security controls that rely on the compromised encryption.

Detection Methods for CVE-2026-42518

Indicators of Compromise

• Unusual access patterns to JavaScript resources or static assets from the e-Sushrut application
• Automated scanning or enumeration of JavaScript files by external IP addresses
• Large-scale data exfiltration following access to client-side resources
• Evidence of decrypted data being accessed by unauthorized parties

Detection Strategies

• Implement Content Security Policy (CSP) headers and monitor for violations that may indicate code inspection attempts
• Review server access logs for bulk downloads of JavaScript files or suspicious patterns of static asset requests
• Deploy web application firewall (WAF) rules to detect and alert on reconnaissance activities
• Monitor for anomalous authentication or data access patterns that may indicate use of compromised encryption keys

Monitoring Recommendations

• Enable detailed logging for all access to e-Sushrut application resources
• Implement runtime application self-protection (RASP) to detect JavaScript inspection attempts
• Monitor for bulk data extraction that could indicate an attacker using compromised keys
• Set up alerts for access to sensitive healthcare data from unusual sources or at unusual times

How to Mitigate CVE-2026-42518

Immediate Actions Required

• Review all client-side JavaScript code in e-Sushrut deployments to identify hardcoded cryptographic keys
• Rotate all encryption keys that may have been exposed through client-side code
• Implement server-side encryption with proper key management infrastructure
• Assess the scope of potentially compromised data and initiate incident response procedures as needed

Patch Information

Refer to the CERT-IN Vulnerability Note CIVN-2026-0207 for official patch information and vendor guidance. Contact the e-Sushrut vendor for specific remediation instructions and updated software versions that address this vulnerability.

Workarounds

• Implement server-side encryption and remove all cryptographic operations from client-side JavaScript
• Deploy a reverse proxy or API gateway to handle encryption/decryption operations server-side
• Implement proper key management using hardware security modules (HSMs) or secure key vaults
• Apply network segmentation to limit access to the vulnerable application while awaiting a patch
• Enable additional authentication requirements for accessing sensitive data as a compensating control

# Example: Review JavaScript files for hardcoded keys
# Search for potential AES key patterns in JavaScript files
grep -rn "CryptoJS\|AES\|encrypt\|decrypt\|secretKey\|iv\|key.*=" /path/to/webroot/*.js

# Implement CSP headers to restrict script execution (example for Apache)
# Add to .htaccess or httpd.conf
Header set Content-Security-Policy "default-src 'self'; script-src 'self'"