CVE-2025-62763 is a Server-Side Request Forgery (SSRF) vulnerability identified in Zimbra Collaboration Server (ZCS) versions prior to 10.1.12. The root cause lies in the configuration of the chat proxy component, which improperly handles user-supplied URLs or requests, allowing an attacker with low privileges to coerce the server into sending HTTP requests to arbitrary internal or external destinations. SSRF vulnerabilities are particularly dangerous because they can bypass perimeter defenses and access internal services that are otherwise inaccessible externally. In this case, the vulnerability does not directly compromise confidentiality or availability but impacts integrity by enabling unauthorized request manipulation. The CVSS 3.1 base score is 5.0, reflecting network attack vector (AV:N), low attack complexity (AC:L), requiring privileges (PR:L), no user interaction (UI:N), and a scope change (S:C) with integrity impact (I:L) but no confidentiality (C:N) or availability (A:N) impact. No public exploits have been reported yet, but the vulnerability’s presence in a widely used collaboration platform makes it a notable risk. The chat proxy’s misconfiguration could allow attackers to pivot within internal networks, potentially accessing sensitive internal APIs or services. The vulnerability was published on October 21, 2025, and no patches or exploit code links are currently available, indicating the need for vigilance and prompt patching once updates are released.

For European organizations, the SSRF vulnerability in Zimbra Collaboration could lead to unauthorized internal network scanning, access to sensitive internal services, and potential lateral movement by attackers. This is especially critical for enterprises and government agencies relying on Zimbra for email and collaboration, as internal services often contain sensitive data or administrative interfaces. Although the vulnerability does not directly expose confidential data or cause denial of service, the integrity impact could facilitate further attacks, such as injecting malicious requests or manipulating internal workflows. Organizations with less mature network segmentation or monitoring are at higher risk. The medium severity rating suggests moderate urgency, but the potential for chained attacks elevates the threat. Given the widespread use of Zimbra in European public and private sectors, the vulnerability could affect critical communication infrastructure, increasing the risk of espionage or disruption in sensitive environments.

1. Upgrade Zimbra Collaboration Server to version 10.1.12 or later as soon as the patch becomes available to address the SSRF vulnerability directly. 2. Until patching is possible, restrict access to the chat proxy component by implementing strict network segmentation and firewall rules that limit outbound requests from the Zimbra server to only trusted internal and external endpoints. 3. Implement monitoring and alerting for unusual outbound HTTP requests originating from the Zimbra server, focusing on requests to internal IP ranges or unexpected external destinations. 4. Review and harden configuration settings related to the chat proxy to ensure it does not accept or forward arbitrary URLs or requests. 5. Conduct internal penetration testing and vulnerability assessments to detect potential SSRF exploitation paths. 6. Educate administrators about the risks of SSRF and the importance of applying patches promptly. 7. Employ web application firewalls (WAFs) with SSRF detection capabilities to provide an additional layer of defense.