CVE-2026-27823 in EGroupware
Summary
by MITRE • 07/20/2026
A vulnerability has been identified in EGroupware that may lead to Remote Code Execution (RCE). The issue allows an authenticated attacker to execute arbitrary commands on the server. If user self-registration is enabled, the vulnerability may be exploitable without prior authentication. The vulnerability stems from improper authorization checks combined with a file write primitive and an arbitrary file read vulnerability, which together enable full system compromise. This has been patched in versions 26.2.20260224 and 23.1.20260224.
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Analysis
by VulDB Data Team • 07/20/2026
This vulnerability in EGroupware represents a critical remote code execution flaw that demonstrates multiple layered security failures within the application's authorization and input validation mechanisms. The issue arises from insufficient access controls that fail to properly validate user permissions before allowing sensitive operations to proceed. When combined with a file write primitive, attackers can manipulate the system's file structure to inject malicious code, while an arbitrary file read vulnerability provides the capability to exfiltrate sensitive information or gain insight into the application's internal state. The vulnerability is particularly dangerous because it can be exploited by unauthenticated users when self-registration is enabled, creating an attack surface that extends beyond typical authenticated scenarios. This configuration essentially eliminates the authentication barrier that would normally prevent unauthorized access to administrative functions.
The technical exploitation of this vulnerability follows a specific attack pattern that leverages the intersection of multiple security weaknesses. The improper authorization checks create a pathway for privilege escalation where authenticated users can perform actions they should not be permitted to execute. The file write primitive allows attackers to place malicious payloads within the application's directory structure, potentially including web shells or other persistent backdoors. The arbitrary file read component enables reconnaissance activities such as reading configuration files, database credentials, or other sensitive data that could further aid in system compromise. This combination creates a complete attack chain from initial access through privilege escalation and persistence establishment. The vulnerability aligns with common weakness enumerations such as CWE-285 for improper authorization and CWE-74 for injection flaws, demonstrating how multiple security issues can compound to create more severe outcomes than any single weakness alone.
The operational impact of this vulnerability extends far beyond simple data compromise, potentially enabling complete system takeover and persistent access. Attackers who successfully exploit this vulnerability can execute arbitrary commands with the privileges of the web server process, which typically has broad access to system resources including database connections, file system operations, and network communication capabilities. The ability to execute code remotely without authentication when self-registration is enabled creates a particularly severe risk for organizations that have not properly configured their application security settings. Organizations may face data breaches, service disruption, and potential lateral movement within their networks as attackers establish persistence and expand their access. This vulnerability could also facilitate further attacks against other systems within the organization's infrastructure, especially if the compromised server has access to internal resources or sensitive databases.
Mitigation strategies for this vulnerability should focus on immediate patching of affected versions, with particular attention to the specific version ranges mentioned in the advisory. Organizations must ensure that EGroupware installations are updated to either version 26.2.20260224 or 23.1.20260224 as these releases contain the necessary security fixes. Beyond patch management, administrators should disable self-registration functionality if it is not required for business operations, as this significantly reduces the attack surface by preventing unauthenticated exploitation. Additional security measures include implementing proper network segmentation to limit access to the application server, establishing robust monitoring for unusual file system activities or command execution patterns, and conducting regular security assessments of web applications. Organizations should also consider implementing web application firewalls to detect and block malicious payloads attempting to exploit similar vulnerabilities, while maintaining detailed audit logs to support incident response activities. The vulnerability underscores the importance of defense in depth strategies and proper access control implementations that prevent unauthorized privilege escalation even when individual security controls fail.