CVE-2025-31991: HCL DevOps Velocity Auth Bypass Flaw

CVE-2025-31991 Overview

CVE-2025-31991 is an improper restriction of excessive authentication attempts vulnerability affecting HCL DevOps Velocity. The application's rate limiting mechanism for user login attempts is not being properly enforced, which allows attackers to conduct brute-force attacks beyond the configured unsuccessful login attempt limit. This weakness (CWE-307) enables adversaries to systematically guess user credentials without being blocked or throttled after reaching the failed attempt threshold.

Critical Impact

Attackers can bypass login rate limiting protections to perform unlimited brute-force attacks against user accounts, potentially compromising credentials and gaining unauthorized access to the DevOps Velocity platform.

Affected Products

• HCL DevOps Velocity versions prior to 5.1.7

Discovery Timeline

• 2026-04-13 - CVE CVE-2025-31991 published to NVD
• 2026-04-13 - Last updated in NVD database

Technical Details for CVE-2025-31991

Vulnerability Analysis

This vulnerability stems from improper enforcement of rate limiting controls on the authentication endpoint. While HCL DevOps Velocity implements a mechanism intended to restrict the number of failed login attempts, the enforcement logic contains a flaw that allows attackers to circumvent these restrictions. This creates a significant authentication weakness that undermines the application's defense against credential stuffing and brute-force attacks.

The vulnerability is accessible over the network without requiring user interaction. While exploitation requires high privileges according to the CVSS assessment, successful exploitation can have cross-scope impact on the integrity of the system. The attack complexity is low, making it relatively straightforward for attackers to exploit once they identify the rate limiting bypass technique.

Root Cause

The root cause is classified as CWE-307 (Improper Restriction of Excessive Authentication Attempts). The rate limiting implementation in HCL DevOps Velocity fails to properly track and enforce the configured limit on unsuccessful login attempts. This could be due to issues such as:

• Improper session or request tracking that allows rate limit counters to be reset
• Inconsistent enforcement across different authentication endpoints
• Logic errors in the rate limiting validation code
• Lack of proper synchronization when checking attempt counts

Attack Vector

The attack vector for this vulnerability is network-based. An attacker can target the login endpoint of HCL DevOps Velocity from a remote location. The exploitation process involves:

1. The attacker identifies the authentication endpoint of the target HCL DevOps Velocity instance
2. The attacker initiates multiple login attempts with different password combinations
3. Despite the application's intended rate limiting, the attacker discovers the enforcement mechanism can be bypassed
4. The attacker continues brute-force attempts without being blocked, eventually guessing valid credentials
5. Upon successful credential discovery, the attacker gains unauthorized access to the platform

The vulnerability does not require any special tools beyond standard HTTP request capabilities. Attackers can leverage common password lists and automated tools to accelerate the brute-force process.

Detection Methods for CVE-2025-31991

Indicators of Compromise

• High volume of failed authentication attempts from single or multiple IP addresses against user accounts
• Successful login events following a pattern of numerous failed attempts that should have triggered account lockout
• Authentication logs showing failed attempt counts exceeding configured thresholds without lockout enforcement
• Unusual login activity patterns suggesting automated credential testing

Detection Strategies

• Implement external monitoring of authentication logs to detect brute-force patterns independently of the application's rate limiting
• Deploy web application firewall (WAF) rules to detect and block excessive login attempts at the network perimeter
• Configure SIEM alerts for authentication anomalies including high failed login rates and suspicious successful logins
• Monitor for automated attack tool signatures in user-agent strings and request patterns

Monitoring Recommendations

• Enable detailed authentication logging including timestamps, source IPs, and attempt outcomes
• Set up real-time alerting for login attempt volumes exceeding normal baselines
• Implement IP reputation monitoring to identify known malicious sources targeting authentication endpoints
• Review authentication logs regularly for patterns indicating ongoing brute-force campaigns

How to Mitigate CVE-2025-31991

Immediate Actions Required

• Upgrade HCL DevOps Velocity to version 5.1.7 or later immediately
• Implement additional network-level rate limiting using a reverse proxy or WAF as a compensating control
• Enable multi-factor authentication (MFA) for all user accounts to reduce brute-force attack effectiveness
• Review authentication logs for evidence of past exploitation attempts
• Enforce strong password policies to increase brute-force resistance

Patch Information

HCL has released a security patch in HCL DevOps Velocity version 5.1.7 that addresses this rate limiting bypass vulnerability. Organizations should upgrade to this version or later to remediate the issue. For detailed patch information, refer to the HCL Software Knowledge Base Article.

Workarounds

• Deploy a reverse proxy or load balancer in front of HCL DevOps Velocity with properly configured rate limiting rules
• Implement IP-based blocking or CAPTCHA challenges after a defined number of failed login attempts at the network layer
• Restrict access to the authentication endpoint to known IP ranges where possible
• Consider implementing account lockout policies at the directory service level if integrated with LDAP or Active Directory
• Monitor and temporarily block IP addresses exhibiting brute-force behavior using intrusion prevention systems

# Example: Configure nginx rate limiting as a compensating control
# Add to nginx configuration for the DevOps Velocity proxy

# Define rate limiting zone (10 requests per second per IP)
limit_req_zone $binary_remote_addr zone=login_limit:10m rate=10r/s;

# Apply rate limiting to login endpoint
location /api/login {
    limit_req zone=login_limit burst=20 nodelay;
    limit_req_status 429;
    proxy_pass http://devops-velocity-backend;
}