Synacor Zimbra Collaboration Suite (ZCS) Server-Side Request Forgery Vulnerability
CVE-2020-7796 · Synacor Zimbra Collaboration Suite · Published 2020-02-18
How bad would it be?
9.8 out of 10
CVSS rates it critical: about as damaging as flaws get.
How likely is it to be used?
94%
Estimated chance of exploitation in the next 30 days, among the top 1% of all scored flaws (EPSS, 2026-10-29).
Is it already being used?
Yes
CISA has seen it exploited in real attacks. For US government agencies the fix is deadline passed 234 days ago (2026-03-10).
What CISA says to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Synacor Zimbra Collaboration Suite (ZCS) contains a server-side request forgery vulnerability if WebEx zimlet installed and zimlet JSP is enabled.
Understand the kind of weakness behind this flaw. These resources teach the weakness, rather than reproduce this specific CVE. Follow the vendor's advice above to fix the affected product.
Server-side request forgery
Input makes a server send a request to an unintended destination.
CWE is a catalogue of weakness types. Labels come from the sources shown and can differ or change. Resource matches reviewed 16 October 2026.
On SentryFeed
No story in the last 14 days has mentioned it.
Exploited flaws from CISA's KEV catalogue. Chance of exploitation from EPSS by FIRST. Descriptions and scores from the NVD. This product uses the NVD API but is not endorsed or certified by the NVD.