CVE-2026-25773: Focalboard SQL Injection Vulnerability

CVE-2026-25773 Overview

CVE-2026-25773 is a Second-Order SQL Injection vulnerability affecting Focalboard version 8.0. The vulnerability exists because the application fails to sanitize category IDs before incorporating them into dynamic SQL statements when reordering categories. An attacker can inject a malicious SQL payload into the category ID field, which is stored in the database and later executed unsanitized when the category reorder API processes the stored value. This Time-Based Blind SQL Injection allows an authenticated attacker to exfiltrate sensitive data including password hashes of other users.

Critical Impact

This vulnerability allows authenticated attackers to extract sensitive database information including user password hashes through Time-Based Blind SQL Injection techniques. Note: Focalboard as a standalone product is no longer maintained and no fix will be issued.

Affected Products

• Focalboard version 8.0 (standalone product - unsupported)

Discovery Timeline

• 2026-04-03 - CVE-2026-25773 published to NVD
• 2026-04-03 - Last updated in NVD database

Technical Details for CVE-2026-25773

Vulnerability Analysis

This vulnerability is classified as CWE-89 (Improper Neutralization of Special Elements used in an SQL Command). The flaw represents a Second-Order SQL Injection pattern, which is particularly dangerous because the malicious payload is not immediately executed. Instead, the injected SQL is first stored in the database through normal application functionality, then later retrieved and executed in a different context where input sanitization was not applied.

The attack targets the category reordering functionality in Focalboard. When a user reorders categories, the application accepts category IDs and stores them. The vulnerability manifests when these stored category IDs are later incorporated into dynamically constructed SQL queries without proper parameterization or escaping.

Root Cause

The root cause is the lack of input sanitization on the category ID field before it is used in SQL statement construction. Focalboard version 8.0 trusts data retrieved from its own database without re-validating it, assuming that data stored internally is safe. This assumption fails when an attacker initially provides a malicious category ID value that bypasses front-end validation but contains SQL injection payloads.

Attack Vector

The attack is network-based and requires authenticated access to the Focalboard application. An attacker with low privileges can exploit this vulnerability through the following attack flow:

1. The attacker creates or modifies a category with a malicious SQL payload embedded in the category ID field
2. The malicious payload is stored in the database
3. When the category reorder API is triggered (either by the attacker or another user), the stored malicious value is retrieved and incorporated into a SQL query
4. The Time-Based Blind SQL Injection payload executes, allowing the attacker to infer database contents through response timing analysis
5. The attacker iteratively extracts sensitive data such as password hashes character by character

The Time-Based Blind technique typically uses database-specific sleep functions (such as SLEEP() in MySQL or pg_sleep() in PostgreSQL) to create measurable delays when specific conditions are true, enabling data exfiltration without direct query output.

For technical implementation details and the codebase, refer to the GitHub Focalboard Repository.

Detection Methods for CVE-2026-25773

Indicators of Compromise

• Unusual database query execution times, particularly queries involving category operations taking significantly longer than normal
• Database logs showing SQL syntax errors or unexpected query patterns in category-related tables
• HTTP request logs containing suspicious characters in category ID parameters (single quotes, semicolons, SQL keywords like SLEEP, WAITFOR, BENCHMARK)
• Multiple sequential requests to the category reorder endpoint with varying response times

Detection Strategies

• Implement SQL query logging and analysis to detect anomalous query patterns or execution times
• Monitor application logs for category API endpoints receiving malformed or unusually long category ID values
• Deploy Web Application Firewall (WAF) rules to detect SQL injection patterns in request parameters
• Use database activity monitoring to alert on queries with embedded time-delay functions

Monitoring Recommendations

• Enable detailed logging on database servers to capture query execution times and identify potential Time-Based Blind SQL Injection attempts
• Configure alerting for category reorder API requests that exceed normal response time thresholds
• Implement anomaly detection for authenticated user sessions making unusual patterns of API calls to category endpoints
• Review and audit database access logs periodically for signs of data exfiltration attempts

How to Mitigate CVE-2026-25773

Immediate Actions Required

• Discontinue use of Focalboard standalone version 8.0 as it is unsupported and will not receive security patches
• Migrate to Mattermost Boards (the supported successor) or an alternative project management solution
• If immediate migration is not possible, restrict network access to the Focalboard instance to trusted users only
• Implement a Web Application Firewall (WAF) with SQL injection detection rules as an interim protective measure

Patch Information

No patch will be issued. Focalboard as a standalone product is no longer maintained by the Mattermost community. Organizations using Focalboard should plan migration to a supported alternative. The GitHub Focalboard Repository contains the source code for organizations that wish to implement their own fix, though this approach requires ongoing maintenance responsibility.

Workarounds

• Implement network-level access controls to limit who can access the Focalboard application
• Deploy a reverse proxy with WAF capabilities configured to block SQL injection patterns in API requests
• Disable or restrict access to the category reorder API endpoint if the functionality is not critical to operations
• Conduct a security review and consider implementing input validation at the application level if maintaining a custom fork
• Rotate all user credentials stored in the Focalboard database as a precautionary measure if compromise is suspected

For organizations maintaining custom deployments, consider implementing parameterized queries for all database operations involving category IDs:

-- Example of parameterized query pattern to prevent SQL injection
-- Replace dynamic SQL construction with prepared statements
-- Ensure category IDs are validated as proper identifiers before use
-- This approach prevents injected payloads from being interpreted as SQL code