RoundCube Webmail Deserialization of Untrusted Data Vulnerability - Active in CISA KEV catalog.
Description
RoundCube Webmail Deserialization of Untrusted Data Vulnerability - Active in CISA KEV catalog.
AI Analyst Comment
Remediation
FEDERAL DEADLINE: March 12, 2026 (20 days). Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. FEDERAL DEADLINE: March 12, 2026 (20 days). Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA KEV Details
Deadline: March 12, 2026
Required Action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Description Summary:
Roundcube Webmail versions before 1.5.10 and 1.6.11 are vulnerable to remote code execution via PHP object deserialization triggered by an unvalidated _from parameter in upload.php.
Executive Summary:
Roundcube Webmail is susceptible to critical remote code execution through deserialization of untrusted data, and this vulnerability is currently being exploited in the wild.
Vulnerability Details
CVE-ID: CVE-2025-49113
Affected Software: Roundcube Webmail
Affected Versions: 0 up to 1.5.10, 1.6.0 up to 1.6.11
Vulnerability: The application fails to validate the _from parameter within the upload.php file, which allows authenticated users to trigger a PHP object deserialization flaw. This mechanism enables an attacker to achieve remote code execution on the underlying server.
Business Impact
Successful exploitation of this vulnerability allows an attacker to execute arbitrary code with the privileges of the web application, resulting in a total compromise of the mail server. Given the CVSS score of 9.5, this flaw poses a severe risk to confidentiality, integrity, and availability. Organizations using Roundcube should expect potential data theft, lateral movement, or complete system takeover if not remediated immediately.
Remediation Plan
Immediate Action: Upgrade to Roundcube Webmail version 1.5.10 or 1.6.11 immediately to address the insecure deserialization flaw.
Proactive Monitoring: Monitor server logs for suspicious requests targeting upload.php or unusual process execution patterns originating from the web server user.
Compensating Controls: Deploy a Web Application Firewall (WAF) with rules configured to inspect and sanitize serialized PHP objects in URL parameters, though such measures are temporary and do not replace the necessity of patching.
Exploitation Status
Public Exploit Available: Yes, a weaponized exploit is available via Metasploit and ExploitDB.
Analyst Notes: This vulnerability is confirmed to be actively exploited in the wild as of February 19, 2026. Due to the availability of weaponized exploits and its inclusion in the CISA KEV catalog, the risk of compromise is extremely high.
Analyst Recommendation
The severity of this vulnerability, combined with its active exploitation and weaponized status, necessitates an immediate emergency patch cycle. All instances of Roundcube Webmail must be updated to the provided fixed versions without delay to prevent unauthorized system access and potential data breaches.