CVE-2026-42513: e-Sushrut Auth Bypass Vulnerability

CVE-2026-42513 Overview

This vulnerability exists in e-Sushrut due to improper authentication logic that relies on client-side response parameters to determine authentication status. A remote attacker could exploit this vulnerability by intercepting and modifying the server response. Successful exploitation of this vulnerability could allow the attacker to bypass authentication and gain unauthorized access to user accounts on the targeted system.

Critical Impact

Remote attackers can bypass authentication mechanisms and gain unauthorized access to user accounts, potentially compromising sensitive healthcare data managed by the e-Sushrut hospital management system.

Affected Products

• e-Sushrut Hospital Management System

Discovery Timeline

• 2026-04-29 - CVE CVE-2026-42513 published to NVD
• 2026-04-29 - Last updated in NVD database

Technical Details for CVE-2026-42513

Vulnerability Analysis

The vulnerability stems from a fundamental security design flaw where the e-Sushrut application trusts client-side response data to make authentication decisions. This architectural weakness violates the principle of never trusting client-provided data, particularly for security-critical operations like authentication.

The application appears to evaluate authentication success or failure based on parameters returned in server responses that can be intercepted and manipulated by an attacker positioned between the client and server. This type of authentication bypass represents a significant security risk as it allows complete circumvention of access controls without requiring valid credentials.

Healthcare management systems like e-Sushrut typically contain highly sensitive patient information, medical records, and administrative data, making this vulnerability particularly concerning from both a security and regulatory compliance perspective.

Root Cause

The root cause of this vulnerability is the improper implementation of authentication logic that relies on client-side response parameters for determining user authentication status. Instead of validating authentication on the server-side with proper session management and cryptographic verification, the application exposes authentication decision points that can be manipulated through response interception.

Attack Vector

The attack is network-based and requires no user interaction or prior privileges. An attacker can exploit this vulnerability by:

1. Positioning themselves to intercept network traffic between a legitimate user and the e-Sushrut server (man-in-the-middle position)
2. Capturing the server's authentication response when a login attempt is made
3. Modifying the response parameters that indicate authentication status (e.g., changing a failure flag to success, or injecting valid session tokens)
4. Forwarding the modified response to the client, which then grants access based on the tampered authentication status

This attack methodology requires the ability to intercept and modify HTTP/HTTPS traffic, which may be achieved through various techniques including ARP spoofing, DNS hijacking, or compromised network infrastructure. For detailed technical information, refer to the CERT-IN Security Advisory CIVN-2026-0207.

Detection Methods for CVE-2026-42513

Indicators of Compromise

• Unusual login patterns where authentication succeeds despite failed credential validation in server logs
• Discrepancies between server-side authentication logs and client-side session establishment
• Network traffic anomalies indicating potential man-in-the-middle activity targeting e-Sushrut endpoints
• Multiple successful logins from different geographic locations within short timeframes for the same user account

Detection Strategies

• Implement network intrusion detection rules to identify potential response tampering attacks against e-Sushrut authentication endpoints
• Monitor authentication logs for inconsistencies between credential validation results and session creation events
• Deploy application-layer monitoring to detect authentication bypass attempts
• Correlate server-side authentication failures with subsequent authorized session activities

Monitoring Recommendations

• Enable comprehensive logging of all authentication attempts, including both client-side and server-side validation results
• Implement real-time alerting for authentication anomalies such as successful logins following failed credential checks
• Monitor network traffic patterns for signs of interception or tampering on authentication-related communications
• Establish baseline authentication behavior patterns to identify deviations that may indicate exploitation attempts

How to Mitigate CVE-2026-42513

Immediate Actions Required

• Restrict network access to e-Sushrut instances to trusted networks only until a patch is available
• Implement additional network-layer authentication controls such as VPN requirements for accessing the application
• Enable HTTPS with certificate pinning to prevent man-in-the-middle attacks
• Review and audit all user accounts for signs of unauthorized access

Patch Information

Organizations should monitor the CERT-IN Security Advisory CIVN-2026-0207 for official patch availability and remediation guidance from the vendor. Apply security updates as soon as they become available.

Workarounds

• Deploy a Web Application Firewall (WAF) configured to inspect and validate authentication responses for tampering
• Implement network segmentation to isolate e-Sushrut servers from untrusted network segments
• Consider deploying a reverse proxy with response integrity validation capabilities
• Enable multi-factor authentication if supported to add an additional authentication layer that cannot be bypassed through response manipulation

# Example: Network access restriction using iptables
# Restrict e-Sushrut access to trusted internal networks only
iptables -A INPUT -p tcp --dport 443 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 192.168.0.0/16 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP