CVE-2026-25560: Wekan LDAP Auth Bypass Vulnerability

CVE-2026-25560 Overview

CVE-2026-25560 is an LDAP filter injection vulnerability affecting WeKan versions prior to 8.19. The vulnerability exists in the LDAP authentication mechanism where user-supplied username input is incorporated into LDAP search filters and DN-related values without adequate escaping. This allows an attacker to manipulate LDAP queries during authentication, potentially bypassing authentication controls or extracting sensitive directory information.

Critical Impact

Unauthenticated attackers can manipulate LDAP queries to bypass authentication or extract sensitive directory information from the LDAP server.

Affected Products

• WeKan versions prior to 8.19
• WeKan installations using LDAP authentication
• Self-hosted WeKan deployments with LDAP directory integration

Discovery Timeline

• 2026-02-07 - CVE-2026-25560 published to NVD
• 2026-02-10 - Last updated in NVD database

Technical Details for CVE-2026-25560

Vulnerability Analysis

This LDAP injection vulnerability (CWE-90) stems from improper neutralization of special characters used in LDAP queries. When a user attempts to authenticate via LDAP, the WeKan application constructs an LDAP search filter using the user-supplied username. The application fails to properly sanitize or escape special LDAP metacharacters before incorporating the username into the filter, allowing attackers to inject malicious LDAP filter syntax.

The vulnerability is remotely exploitable without authentication, meaning an attacker only needs network access to the WeKan login page. Successful exploitation could allow authentication bypass, unauthorized data access, or enumeration of LDAP directory contents depending on the LDAP server configuration and the attacker's crafted payload.

Root Cause

The root cause lies in the packages/wekan-ldap/server/ldap.js file where user-supplied usernames are directly concatenated into LDAP filter expressions without proper escaping. The LDAP search field configuration allows multiple fields to be searched, and for each field, the username is inserted directly into the filter string (${item}=${username}). Without escaping LDAP special characters like *, (, ), \, and null bytes, an attacker can break out of the intended filter context and inject arbitrary LDAP filter logic.

Attack Vector

The attack is network-based and requires no authentication or user interaction. An attacker can submit a specially crafted username through the WeKan login form that contains LDAP metacharacters. These characters modify the structure of the resulting LDAP query, potentially allowing the attacker to:

• Bypass authentication by constructing always-true filter conditions
• Enumerate valid usernames or other LDAP attributes
• Extract sensitive information from the LDAP directory through blind injection techniques

       }
     }
 
-    const usernameFilter = this.options.User_Search_Field.split(',').map((item) => `(${item}=${username})`);
+    // Escape the username to prevent LDAP injection
+    const escapedUsername = escapedToHex(username);
+    const usernameFilter = this.options.User_Search_Field.split(',').map((item) => `(${item}=${escapedUsername})`);
 
     if (usernameFilter.length === 0) {
       Log.error('LDAP_LDAP_User_Search_Field not defined');

Source: GitHub Commit Details

Detection Methods for CVE-2026-25560

Indicators of Compromise

• Unusual login attempts with usernames containing LDAP metacharacters such as *, (, ), \, or null bytes
• Authentication logs showing malformed usernames or unexpected LDAP query patterns
• Failed or anomalous LDAP bind operations in directory server logs
• Multiple authentication attempts from the same source with varying username payloads indicative of probing

Detection Strategies

• Implement input validation logging to capture login attempts with suspicious characters in username fields
• Monitor LDAP server logs for malformed queries, unusual search patterns, or unexpected filter structures
• Deploy web application firewall (WAF) rules to detect and block LDAP injection patterns in authentication parameters
• Configure SIEM alerts for authentication anomalies associated with LDAP-integrated applications

Monitoring Recommendations

• Enable detailed logging for WeKan authentication events and correlate with LDAP server logs
• Monitor for high volumes of failed authentication attempts that may indicate injection probing
• Track LDAP query response times as injection attacks may cause unusual query patterns
• Review network traffic to LDAP servers for anomalous query sizes or frequencies

How to Mitigate CVE-2026-25560

Immediate Actions Required

• Upgrade WeKan to version 8.19 or later immediately
• Review authentication logs for evidence of exploitation attempts
• Implement network segmentation to limit access to the WeKan application and LDAP servers
• Consider temporarily disabling LDAP authentication until the patch is applied if immediate upgrade is not possible

Patch Information

The vulnerability has been addressed in WeKan version 8.19. The fix implements proper escaping of user-supplied input using the escapedToHex() function before incorporating usernames into LDAP filter expressions. Organizations should apply the update by following their standard software update procedures for WeKan deployments.

For detailed patch information, refer to the GitHub Commit Details.

Workarounds

• Deploy a web application firewall (WAF) with LDAP injection detection rules in front of WeKan
• Implement additional input validation at the network perimeter to filter LDAP metacharacters from authentication requests
• Restrict network access to the WeKan login endpoint to trusted networks or VPN users only
• Consider using alternative authentication methods (local accounts, OAuth) until the patch can be applied

# Example: Restrict WeKan access to internal network via iptables
iptables -A INPUT -p tcp --dport 80 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP