CVE-2026-23958: DataEase Auth Bypass Vulnerability

CVE-2026-23958 Overview

DataEase, an open source data visualization analysis tool, contains a critical weakness in its JWT token implementation. Prior to version 2.10.19, DataEase uses the MD5 hash of the user's password as the JWT signing secret. This deterministic secret derivation allows an attacker to brute-force the admin's password by exploiting unmonitored API endpoints that verify JWT tokens. This vulnerability is classified under CWE-522 (Insufficiently Protected Credentials).

Critical Impact

Attackers can brute-force administrator passwords by exploiting the predictable JWT signing secret, potentially gaining full administrative access to DataEase instances.

Affected Products

• DataEase versions prior to 2.10.19
• Self-hosted DataEase installations using default authentication
• DataEase deployments with exposed API endpoints

Discovery Timeline

• 2026-01-22 - CVE-2026-23958 published to NVD
• 2026-01-22 - Last updated in NVD database

Technical Details for CVE-2026-23958

Vulnerability Analysis

The vulnerability stems from a fundamental design flaw in how DataEase implements JWT authentication. Instead of using a cryptographically secure, randomly generated secret for signing JWT tokens, the application derives the signing secret directly from the MD5 hash of the user's password. This approach creates a dangerous relationship between the authentication token verification mechanism and the user's credential.

When an attacker can observe or interact with API endpoints that validate JWT tokens, they can systematically test password guesses by generating JWT tokens signed with MD5 hashes of candidate passwords. If a token is successfully validated, the attacker has effectively confirmed the correct password. This attack bypasses traditional rate limiting on login endpoints since the brute-force occurs through token verification endpoints that may not have equivalent monitoring or throttling.

Root Cause

The root cause is the use of deterministic secret derivation for JWT signing. By using the MD5 hash of a user's password as the JWT secret, the application creates a direct mathematical relationship between the password and the signing key. This violates the principle that signing secrets should be independent, random, and not derivable from user credentials.

The use of MD5 further compounds the issue as it is a weak hashing algorithm that is computationally inexpensive to compute, making brute-force attacks more feasible. Modern systems should use cryptographically secure random number generators to create JWT secrets that are stored securely and independent of any user data.

Attack Vector

The attack is network-based and can be executed without any user interaction or prior authentication. An attacker targeting a vulnerable DataEase instance would:

1. Identify API endpoints that accept and validate JWT tokens
2. Generate a list of candidate passwords (dictionary attack or targeted guesses)
3. For each candidate password, compute the MD5 hash
4. Create JWT tokens signed with each MD5 hash
5. Submit tokens to unmonitored API endpoints
6. Observe which token is successfully validated, revealing the correct password

The vulnerability allows unauthenticated remote attackers to determine valid administrator credentials through this offline-style attack performed against the live system.

Detection Methods for CVE-2026-23958

Indicators of Compromise

• Unusual volume of requests to JWT-protected API endpoints from single IP addresses
• Multiple failed token validation attempts followed by successful authentication
• Requests with varying JWT tokens to the same endpoint in rapid succession
• Authentication log entries showing successful admin logins from unexpected sources after periods of elevated API activity

Detection Strategies

• Implement anomaly detection for API endpoint access patterns, particularly focusing on endpoints that validate JWT tokens
• Monitor for high-frequency requests to authentication-related endpoints that may indicate brute-force attempts
• Enable and review authentication audit logs for successful logins following unusual API activity patterns
• Deploy network-level monitoring to detect systematic token validation attempts from external sources

Monitoring Recommendations

• Configure alerts for repeated requests to JWT-validating endpoints from the same source
• Implement rate limiting and logging on all API endpoints that perform token validation
• Review access logs for patterns consistent with password enumeration attacks
• Monitor for successful admin authentications from IP addresses with previous suspicious activity

How to Mitigate CVE-2026-23958

Immediate Actions Required

• Upgrade DataEase to version 2.10.19 or later immediately
• Audit authentication logs for signs of exploitation prior to patching
• Rotate all administrator passwords after upgrading to ensure any potentially compromised credentials are invalidated
• Review and restrict network access to DataEase API endpoints to trusted sources where possible

Patch Information

The vulnerability has been fixed in DataEase version 2.10.19. The patch implements proper JWT signing secret generation that is independent of user credentials. Organizations should upgrade to this version or later as soon as possible. For detailed information about the security fix, refer to the GitHub Security Advisory.

Workarounds

• No known workarounds are available for this vulnerability according to the vendor advisory
• As a temporary measure, restrict network access to DataEase instances to trusted internal networks only
• Consider placing DataEase behind a reverse proxy with additional rate limiting and authentication controls
• Monitor API access logs closely until patching can be completed

# Upgrade DataEase to patched version
# Follow vendor documentation for your deployment method

# Example: Restrict access via firewall (temporary measure)
# Allow only trusted IP ranges to access DataEase
iptables -A INPUT -p tcp --dport 8100 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 8100 -j DROP