CVE-2026-42516: e-Sushrut Auth Bypass Vulnerability

CVE-2026-42516 Overview

This vulnerability exists in e-Sushrut, a healthcare management system, due to improper authorization checks during resource access. An authenticated attacker could exploit this vulnerability by manipulating encoded parameters in the request URL to gain unauthorized access to patient accounts on the targeted system. This represents a classic Insecure Direct Object Reference (IDOR) vulnerability classified under CWE-639 (Authorization Bypass Through User-Controlled Key).

Critical Impact

Authenticated attackers can bypass authorization controls to access sensitive patient medical records and personal health information by manipulating URL parameters.

Affected Products

• e-Sushrut Healthcare Management System

Discovery Timeline

• April 29, 2026 - CVE-2026-42516 published to NVD
• April 29, 2026 - Last updated in NVD database

Technical Details for CVE-2026-42516

Vulnerability Analysis

The vulnerability stems from inadequate authorization validation when the application processes user requests to access patient resources. When an authenticated user attempts to access patient data, the application relies on user-controlled parameters within the URL to identify which patient record to retrieve. The application fails to verify that the authenticated user has legitimate authorization to access the requested patient's information.

This type of vulnerability, known as Insecure Direct Object Reference (IDOR), allows attackers to perform horizontal privilege escalation by accessing data belonging to other patients within the system. The attack requires network access and low-privilege authentication, making it exploitable by any user with valid credentials to the e-Sushrut system.

Root Cause

The root cause is improper authorization checks during resource access (CWE-639: Authorization Bypass Through User-Controlled Key). The application uses encoded parameters in URLs to reference patient accounts but does not properly validate whether the authenticated user has permission to access the referenced patient record. This allows manipulation of these encoded parameters to access arbitrary patient accounts.

Attack Vector

The attack is network-based and requires low-privilege authentication to the e-Sushrut system. An attacker must first obtain valid credentials to authenticate to the application. Once authenticated, the attacker can analyze URL patterns used to access their own patient data and identify the encoded parameters that reference specific patient accounts.

By manipulating these encoded parameters—potentially through techniques like Base64 decoding, modifying the underlying identifier, and re-encoding—the attacker can craft requests to access other patient accounts. The application processes these modified requests without verifying authorization, returning sensitive medical records belonging to other patients.

For additional technical details, see the CERT-IN Vulnerability Note CIVN-2026-0207.

Detection Methods for CVE-2026-42516

Indicators of Compromise

• Unusual patterns of patient record access by individual user accounts
• Sequential or systematic access attempts to multiple patient records in rapid succession
• URL parameter tampering detected in web application logs
• Encoded parameter values that don't match the authenticated user's expected patient associations

Detection Strategies

• Implement logging and alerting for access control violations where users attempt to access resources outside their authorized scope
• Monitor for anomalous access patterns where a single user account accesses an unusually high number of patient records
• Deploy web application firewall (WAF) rules to detect parameter manipulation attempts
• Analyze application logs for requests containing modified or suspicious encoded parameter values

Monitoring Recommendations

• Enable detailed access logging for all patient record retrieval operations
• Configure alerts for access control failures or authorization exceptions in the application
• Implement user behavior analytics to detect abnormal data access patterns
• Review audit logs regularly for evidence of unauthorized patient record access

How to Mitigate CVE-2026-42516

Immediate Actions Required

• Implement proper server-side authorization checks that verify the authenticated user has legitimate access to the requested patient record
• Replace predictable or easily manipulated identifiers with cryptographically random, non-guessable tokens
• Add session-based validation to ensure users can only access patient records they are authorized to view
• Conduct an audit of access logs to identify any potential exploitation that may have occurred

Patch Information

Organizations should consult the CERT-IN Vulnerability Note CIVN-2026-0207 for official patch information and vendor guidance. Contact the e-Sushrut vendor directly for the latest security updates addressing this authorization bypass vulnerability.

Workarounds

• Implement additional access control layers at the network level to restrict which users can access patient data endpoints
• Deploy a web application firewall with rules to detect and block parameter tampering attempts
• Temporarily restrict access to sensitive patient record features until a patch can be applied
• Enable enhanced logging and monitoring to detect exploitation attempts while awaiting a permanent fix