CVE-2025-70030: Sunbird-Ed Portal ReDoS Vulnerability

CVE-2025-70030 Overview

CVE-2025-70030 is an Inefficient Regular Expression Complexity vulnerability (CWE-1333) discovered in Sunbird-Ed SunbirdEd-portal version 1.13.4. This type of vulnerability, commonly known as Regular Expression Denial of Service (ReDoS), occurs when specially crafted input causes the regular expression engine to take exponential time to evaluate, leading to denial of service conditions.

Critical Impact

This ReDoS vulnerability allows unauthenticated remote attackers to cause a denial of service by sending maliciously crafted input that triggers catastrophic backtracking in vulnerable regular expression patterns.

Affected Products

• Sunbird-Ed SunbirdEd-portal v1.13.4

Discovery Timeline

• 2026-03-09 - CVE CVE-2025-70030 published to NVD
• 2026-03-11 - Last updated in NVD database

Technical Details for CVE-2025-70030

Vulnerability Analysis

This vulnerability is classified under CWE-1333: Inefficient Regular Expression Complexity. The SunbirdEd-portal, an open-source learning management platform, contains a regular expression pattern that is susceptible to catastrophic backtracking. When processing user-supplied input, the vulnerable regex pattern can be exploited to consume excessive CPU resources, effectively rendering the application unresponsive to legitimate requests.

The attack can be executed remotely over the network without any authentication requirements or user interaction, making it particularly concerning for publicly accessible deployments of SunbirdEd-portal.

Root Cause

The root cause stems from the implementation of a regular expression with nested quantifiers or overlapping patterns that create exponential backtracking scenarios. When the regex engine attempts to match specially crafted input strings, it must explore an exponentially growing number of possible matching paths before determining that no match exists. This computational complexity can cause the application to hang or become unresponsive.

Attack Vector

An attacker can exploit this vulnerability remotely over the network by submitting specially crafted input strings to the vulnerable endpoint in SunbirdEd-portal. The attack does not require authentication or any special privileges. The malicious input triggers the vulnerable regular expression pattern, causing the server to enter a state of high CPU utilization as the regex engine attempts to process the pathological input. This results in denial of service, affecting the availability of the application for all users.

Technical details and a proof-of-concept demonstrating the vulnerability are available at the GitHub Gist PoC published by the security researcher.

Detection Methods for CVE-2025-70030

Indicators of Compromise

• Abnormal CPU spikes on servers running SunbirdEd-portal without corresponding increases in legitimate traffic
• Application response time degradation or complete unresponsiveness
• Server logs showing repeated requests with unusually long or repetitive string patterns
• Process monitoring indicating the Node.js or JavaScript runtime consuming excessive CPU cycles

Detection Strategies

• Monitor application performance metrics for sudden CPU utilization increases exceeding normal operational baselines
• Implement request timeout mechanisms to identify and terminate long-running regex operations
• Deploy web application firewall (WAF) rules to detect and block requests containing suspicious repetitive patterns
• Configure server-side logging to capture and analyze requests that result in slow response times

Monitoring Recommendations

• Establish baseline performance metrics for SunbirdEd-portal deployments and configure alerts for anomalies
• Implement application-level health checks that can detect when the service becomes unresponsive
• Monitor network traffic patterns for repeated requests targeting known vulnerable endpoints
• Configure resource quotas and process isolation to limit the blast radius of successful exploitation attempts

How to Mitigate CVE-2025-70030

Immediate Actions Required

• Upgrade SunbirdEd-portal to a version that addresses the vulnerable regular expression pattern
• Implement input validation and length restrictions on user-supplied data before regex processing
• Configure request timeouts at the web server and application levels to prevent prolonged CPU consumption
• Deploy rate limiting to reduce the effectiveness of sustained ReDoS attacks

Patch Information

At the time of publication, administrators should monitor the SunbirdEd-portal GitHub repository for security patches addressing this vulnerability. The vendor has been notified, and affected organizations should check for updated releases that remediate the inefficient regular expression pattern.

Workarounds

• Implement input length restrictions on all user-supplied data processed by the vulnerable component
• Deploy a reverse proxy or WAF with regex timeout capabilities to terminate long-running pattern matching operations
• Consider using regex implementations with built-in backtracking protection or timeout mechanisms
• Isolate the vulnerable service in a containerized environment with CPU resource limits to prevent system-wide impact

# Example: Configure nginx timeout to limit request processing time
# Add to nginx server block configuration
location / {
    proxy_pass http://sunbirded-portal;
    proxy_connect_timeout 30s;
    proxy_send_timeout 30s;
    proxy_read_timeout 30s;
}