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Security tracker

CVE-2020-7796: Synacor Zimbra Collaboration Suite (ZCS) Server-Side Request Forgery Vulnerability

In short

Synacor Zimbra Collaboration Suite has a weakness classified as server-side request forgery (CWE-918). CISA added it to its Known Exploited Vulnerabilities catalog on 2026-02-17. NVD lists CVSS 3.1 at 9.8 CRITICAL.

What it is

“Synacor Zimbra Collaboration Suite (ZCS) contains a server-side request forgery vulnerability if WebEx zimlet installed and zimlet JSP is enabled.” — CISA KEV, retrieved 2026-11-01
“Zimbra Collaboration Suite (ZCS) before 8.8.15 Patch 7 allows SSRF when WebEx zimlet is installed and zimlet JSP is enabled.” — NVD, retrieved 2026-11-01

Who is affected

Synacor Zimbra Collaboration Suite. NVD lists the following versions as affected:

  • Versions before 8.8.15
  • Versions version 8.8.15

Exploitation status

CISA KEV added: 2026-02-17. Known ransomware campaign use: Not reported by CISA. Due date CISA set for US federal civilian agencies: 2026-03-10.

Scores

NVD CVSS 3.1: 9.8 CRITICAL; vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H; source [email protected].

EPSS by FIRST: 93.59%; percentile 99.84; score date 2026-10-31. EPSS estimates the probability of exploitation in the next 30 days.

CWE: CWE-918.

Timeline

Source events
DateEvent
2020-02-18T22:15:10.013NVD published
2026-02-17CISA KEV added
2026-03-10CISA KEV due
2026-06-17T03:25:27.790NVD last modified
2026-10-31FIRST EPSS score

CISA 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.” — CISA KEV

What to do

  • Confirm whether you run Synacor Zimbra Collaboration Suite and which version.
  • Apply the vendor update or mitigation in the advisory.
  • Follow CISA’s required action.
  • Review the vendor guidance on signs of compromise.
  • Track the fix through completion.

References

Sources and dates

CISA Known Exploited Vulnerabilities Catalog, version 2026.10.30; retrieved 2026-11-01. CISA KEV data: CC0 1.0. No endorsement by CISA.

NVD retrieved: 2026-11-01. This product uses the NVD API but is not endorsed or certified by the NVD.

EPSS scores by FIRST; score date 2026-10-31.

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