CVE-2026-41276: FlowiseAI Authentication Bypass Vulnerability

CVE-2026-41276 Overview

CVE-2026-41276 is a critical authentication bypass vulnerability in FlowiseAI Flowise, a drag and drop user interface for building customized large language model flows. Prior to version 3.1.0, the vulnerability allows remote attackers to bypass authentication without any prior authentication by exploiting a flaw in the password reset mechanism. The specific vulnerability exists within the resetPassword method of the AccountService class, where no verification is performed to confirm that a password reset token has actually been generated for a user account.

Critical Impact

Unauthenticated attackers can reset any user's password and gain complete account access, potentially compromising sensitive LLM workflows and data.

Affected Products

• FlowiseAI Flowise versions prior to 3.1.0

Discovery Timeline

• April 23, 2026 - CVE CVE-2026-41276 published to NVD
• April 23, 2026 - Last updated in NVD database

Technical Details for CVE-2026-41276

Vulnerability Analysis

This authentication bypass vulnerability (CWE-287) stems from improper validation in the password reset functionality. The vulnerability allows unauthenticated remote attackers to completely bypass authentication mechanisms and take over user accounts. The attack requires network access and some user interaction, but does not require any privileges or prior authentication. Successful exploitation results in complete compromise of confidentiality, integrity, and availability of the affected user account and any associated LLM workflows.

Root Cause

The root cause of this vulnerability lies in the resetPassword method within the AccountService class. The implementation fails to perform a critical validation check: it does not verify that a password reset token has actually been generated for a user account before allowing a password reset. By default, the value of the reset token stored in a user's account is null, or an empty string if they've previously reset their password. This design flaw means that any account without an actively pending reset token effectively has a "known" token value that attackers can exploit.

Attack Vector

The attack exploits the network-accessible /api/v1/account/reset-password endpoint. An attacker who knows (or can guess) a target user's email address can submit a malicious request to this endpoint containing either a null or empty string value as the reset token. Since the application does not validate whether a legitimate reset token was ever generated, this null/empty token matches the default or cleared state in the database, allowing the attacker to reset that user's password to any value of their choosing.

The exploitation flow involves:

1. Identifying a target user's email address (this may be enumerable or obtained through other means)
2. Sending a POST request to /api/v1/account/reset-password with the victim's email and a null or empty string token
3. Setting a new password controlled by the attacker
4. Logging in with the newly set credentials to gain full account access

For detailed technical information, see the GitHub Security Advisory.

Detection Methods for CVE-2026-41276

Indicators of Compromise

• Unexpected password reset activity in application logs without corresponding reset token generation requests
• Multiple password reset attempts targeting different user accounts from the same source IP
• Successful login events following password resets that users did not initiate
• API requests to /api/v1/account/reset-password containing null, empty, or unusually short token values

Detection Strategies

• Monitor API access logs for requests to /api/v1/account/reset-password with missing or empty token parameters
• Implement alerting for password reset completions that lack a corresponding reset initiation event
• Deploy web application firewall (WAF) rules to detect and block password reset requests with null or empty token values
• Review authentication logs for account access patterns indicating compromised credentials

Monitoring Recommendations

• Enable detailed logging for all authentication-related API endpoints
• Configure SIEM alerts for anomalous password reset patterns, particularly high volumes or off-hours activity
• Implement user notification systems to alert account owners of password changes
• Monitor for reconnaissance activity attempting to enumerate valid email addresses

How to Mitigate CVE-2026-41276

Immediate Actions Required

• Upgrade FlowiseAI Flowise to version 3.1.0 or later immediately
• Audit recent password reset activity to identify any suspicious resets that may indicate exploitation
• Force password resets for all administrative and high-privilege accounts as a precautionary measure
• Review access logs for any unauthorized access following suspicious password reset events

Patch Information

The vulnerability has been addressed in FlowiseAI Flowise version 3.1.0. The fix implements proper validation to ensure that a valid, non-null password reset token must exist and match before allowing a password reset operation. Organizations should update to version 3.1.0 or later to remediate this vulnerability. For more details, refer to the GitHub Security Advisory.

Workarounds

• Implement network-level access controls to restrict access to the /api/v1/account/reset-password endpoint to trusted networks only
• Deploy a web application firewall (WAF) rule to block requests with empty or null token values to the password reset endpoint
• Temporarily disable the password reset functionality until the patch can be applied, requiring manual administrator intervention for password resets
• Enable multi-factor authentication (MFA) if available to add an additional layer of protection beyond password-based authentication

# Example: WAF rule to block suspicious password reset requests (conceptual)
# Block requests to password reset endpoint with empty/null token values
# Specific implementation varies by WAF platform
# Consult your WAF documentation for exact configuration syntax