ACTIVELY EXPLOITED

CVE-2025-48700: Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting Vulnerability

Facts
VendorSynacor
ProductZimbra Collaboration Suite (ZCS)
Actively exploitedYes
Added to CISA KEV20 Apr 2026
CISA federal deadline23 Apr 2026
Weakness (CWE)CWE-79

Required action (CISA's text)

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 (NVD)

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

SOURCES

Other Synacor flaws

Data from NVD, CISA KEV, FIRST EPSS and vendor advisories. Updated 10 Nov 2026.