CVE-2026-22243 Overview
A SQL Injection vulnerability has been identified in EGroupware, a web-based groupware server written in PHP. The vulnerability exists in the core components of EGroupware, specifically in the Nextmatch filter processing functionality. Authenticated attackers can exploit this flaw to inject arbitrary SQL commands into the WHERE clause of database queries by leveraging a PHP type juggling issue where JSON decoding converts numeric strings into integers, effectively bypassing the is_int() security check implemented by the application.
Critical Impact
Authenticated attackers can execute arbitrary SQL commands against the underlying database, potentially leading to unauthorized data access, data modification, or complete database compromise.
Affected Products
- EGroupware versions prior to 23.1.20260113
- EGroupware versions prior to 26.0.20260113
Discovery Timeline
- 2026-01-28 - CVE CVE-2026-22243 published to NVD
- 2026-01-29 - Last updated in NVD database
Technical Details for CVE-2026-22243
Vulnerability Analysis
This SQL Injection vulnerability (CWE-89) affects the Nextmatch filter processing component within EGroupware's core architecture. The vulnerability is network-accessible and requires low-privilege authentication to exploit. Once authenticated, an attacker can manipulate filter parameters to inject malicious SQL statements that are processed without proper sanitization.
The core issue stems from how EGroupware processes user-supplied filter data. When filter values are submitted as JSON, the PHP json_decode() function automatically converts numeric string values (e.g., "123") into native integer types. This automatic type conversion creates a security bypass because the application relies on is_int() checks to determine whether a value should be treated as a safe integer parameter or require additional SQL escaping.
Root Cause
The root cause is a PHP type juggling vulnerability that undermines the application's input validation logic. The is_int() function is used as a security gate to distinguish between integer values (considered safe) and string values (requiring SQL escaping). However, when user input passes through json_decode(), numeric strings are automatically cast to integers, causing the security check to pass for attacker-controlled values. This allows malicious SQL payloads that would normally be sanitized to bypass the validation and be directly incorporated into SQL queries.
Attack Vector
The attack is conducted over the network by authenticated users who submit specially crafted JSON payloads to the Nextmatch filter endpoints. The attacker constructs a filter parameter containing a numeric string that, when JSON-decoded, becomes an integer and bypasses validation. The malicious SQL is then injected into the WHERE clause of database queries. This can allow attackers to extract sensitive data, modify database records, or potentially escalate privileges within the application by manipulating user roles or permissions stored in the database.
The vulnerability mechanism exploits the inconsistency between how JSON handles type conversion and how PHP's is_int() function validates input. Attackers can craft payloads where the numeric portion passes validation while appended SQL syntax executes malicious commands. For detailed technical information, refer to the GitHub Security Advisory GHSA-rvxj-7f72-mhrx.
Detection Methods for CVE-2026-22243
Indicators of Compromise
- Unusual or malformed SQL queries in database logs containing unexpected WHERE clause conditions
- HTTP POST requests to Nextmatch filter endpoints with anomalous JSON payloads containing SQL keywords
- Database errors or exceptions indicating SQL syntax errors from filter processing components
- Unexpected data access patterns or bulk data extraction from authenticated user sessions
Detection Strategies
- Implement Web Application Firewall (WAF) rules to detect SQL injection patterns in JSON request bodies
- Monitor database query logs for SQL injection signatures such as UNION SELECT, OR 1=1, or comment sequences (--, /**/)
- Deploy application-layer monitoring to flag requests with numeric strings that contain non-numeric characters in filter parameters
- Analyze authentication logs to identify compromised accounts exhibiting SQL injection attack patterns
Monitoring Recommendations
- Enable detailed logging for the Nextmatch component and filter processing functions
- Set up alerts for database queries with unusually long WHERE clauses or unexpected subqueries
- Monitor for increased database CPU or I/O activity that may indicate data exfiltration attempts
- Implement baseline behavior analysis for authenticated user database query patterns
How to Mitigate CVE-2026-22243
Immediate Actions Required
- Upgrade EGroupware to version 23.1.20260113 or 26.0.20260113 immediately
- Review database audit logs for evidence of SQL injection attempts or successful exploitation
- Implement additional WAF rules to block SQL injection patterns targeting filter endpoints
- Consider temporarily restricting access to the Nextmatch functionality until patching is complete
Patch Information
EGroupware has released patched versions that address this vulnerability. Organizations should update to version 23.1.20260113 for the 23.x branch or version 26.0.20260113 for the 26.x branch. The patches are available through the official GitHub releases:
For complete details on the vulnerability and patch, refer to the GitHub Security Advisory GHSA-rvxj-7f72-mhrx.
Workarounds
- Deploy a reverse proxy or WAF with strict SQL injection filtering rules for all incoming JSON payloads
- Implement network segmentation to limit database access from the EGroupware application server
- Restrict user authentication and enforce principle of least privilege to minimize the pool of potential attackers
- Consider disabling or restricting access to Nextmatch filter functionality until the official patch can be applied
# Example WAF rule for ModSecurity to block SQL injection in JSON bodies
SecRule REQUEST_BODY "@rx (?i)(\b(select|union|insert|update|delete|drop|truncate)\b.*\b(from|into|set)\b)" \
"id:100001,phase:2,deny,status:403,log,msg:'Potential SQL Injection in JSON body'"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
