Synacor

Russia-aligned threat actor TA488 (Void Blizzard, Laundry Bear) exploited CVE-2025-66376, a critical XSS vulnerability in Zimbra Collaboration Suite webmail, for at least five months in 2025 via crafted emails to gain persistent access, exfiltrate user credentials, 2FA codes, and bulk emails from Ukrainian government and US defense industrial base targets.

An attacker can exploit multiple vulnerabilities in Synacor Zimbra to execute arbitrary code, perform cross-site scripting attacks, bypass security measures, disclose confidential information, and carry out unauthorized actions.

A critical cross-site scripting (XSS) vulnerability, affecting Synacor Zimbra Collaboration versions prior to 10.1.19, allows an attacker to achieve remote indirect code injection, potentially leading to session hijacking, data exfiltration, or defacement.

An unauthenticated remote attacker can exploit a Cross-Site Scripting (XSS) vulnerability in the Synacor Zimbra Classic Web Client, allowing the attacker to inject malicious scripts into web pages viewed by other users, potentially leading to session hijacking, data theft, or defacement.

A cross-site scripting (XSS) vulnerability in Synacor Zimbra Collaboration Suite (ZCS) could allow attackers to execute arbitrary JavaScript within a user's session, potentially leading to unauthorized access to sensitive information.