CVE-2026-62644 in Roundcube
Summary
by MITRE • 07/14/2026
In Roundcube Webmail before 1.6.17 and 1.7.x before 1.7.2, the password plugin of the Roundcube Webmail was subject to username spoofing via session data, which could lead to account takeover.
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Analysis
by VulDB Data Team • 07/14/2026
The vulnerability identified in Roundcube Webmail versions prior to 1.6.17 and 1.7.x before 1.7.2 represents a critical authentication bypass flaw that exploits session management weaknesses to enable unauthorized account access. This issue specifically affects the password plugin component of the webmail system, which handles user authentication and credential management functions.
The technical flaw stems from improper validation of username data within session storage mechanisms during password change operations. When users attempt to modify their passwords through the webmail interface, the system stores temporary session data that includes username information. An attacker can manipulate this stored session data to inject malicious username values, effectively spoofing legitimate user identities and gaining unauthorized access to target accounts. This vulnerability operates at the application layer and directly impacts the integrity of the authentication process.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass full account compromise and potential data exfiltration. An attacker exploiting this issue can impersonate any valid user within the system, gaining access to sensitive email communications, personal information, and potentially using compromised accounts for further attacks within the organization. The vulnerability is particularly dangerous because it allows attackers to target specific users without requiring prior knowledge of their passwords, making it a sophisticated account takeover vector.
This weakness maps to CWE-287 which describes improper authentication vulnerabilities in software systems, and aligns with ATT&CK technique T1078 for valid accounts and privilege escalation. Organizations utilizing Roundcube Webmail should immediately implement the available patches released by the development team to address this session data manipulation vulnerability. Additional mitigations include implementing proper input validation for session data, enforcing strict access controls on authentication endpoints, and monitoring session management activities for suspicious patterns.
The vulnerability demonstrates the critical importance of secure session handling in web applications and highlights potential security gaps in password reset and change functionalities. Organizations should conduct comprehensive security assessments of their email systems to identify similar session management weaknesses that could be exploited by threat actors. Regular security updates and proper patch management practices become essential defensive measures against such authentication bypass attacks that can compromise entire user bases through single-point vulnerabilities.
The exploitation of this vulnerability requires minimal technical skill and can be automated, making it particularly attractive to cybercriminals seeking large-scale account takeovers. Organizations should also consider implementing additional security controls such as multi-factor authentication and enhanced session monitoring to provide defense-in-depth against similar attacks targeting authentication systems.