What is CVE-2019-6980?

CVE-2019-6980 is a critical-severity vulnerability in Synacor Zimbra Collaboration Suite, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2019-05-29.

How severe is CVE-2019-6980?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2019-6980 known to be exploited?

3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Deserialization in Synacor Zimbra Collaboration Suite

CVE-2019-6980

Synacor Zimbra Collaboration Suite 8.7.x through 8.8.11 allows insecure object deserialization in the IMAP component.

Vulnerability class: Insecure Deserialization

Published 2019-05-29 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.038 (89.7th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 90th percentile — 89.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.038 · newest: 0.038 · change: 0.000

Affected products

Synacor Zimbra Collaboration Suite — versions 8.7.11, 8.8.9, 8.8.10

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

Public proof-of-concept exploits

References

wiki.zimbra.com/wiki/Zimbra_Security_Advisories (Vendor Advisory)
bugzilla.zimbra.com/show_bug.cgi (Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2019-6980?: CVE-2019-6980 is a critical-severity vulnerability in Synacor Zimbra Collaboration Suite, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2019-05-29.
How severe is CVE-2019-6980?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2019-6980 known to be exploited?: 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.