What is CVE-2014-8563?

CVE-2014-8563 is a critical-severity vulnerability in Synacor Zimbra Collaboration Server, classified under OS Command Injection. CVSS score: 9.8/10. Published 2020-01-27.

How severe is CVE-2014-8563?

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

RCE in Synacor Zimbra Collaboration Server

CVE-2014-8563

Synacor Zimbra Collaboration before 8.0.9 allows plaintext command injection during STARTTLS.

Vulnerability class: Command Injection (OS Command Injection)

Published 2020-01-27 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.025 (84.3th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 84th percentile — 84.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.025 · newest: 0.025 · change: 0.000

Affected products

Synacor Zimbra Collaboration Server

Weakness classification (CWE)

CWE-78 — OS Command Injection

References

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

Frequently asked questions

What is CVE-2014-8563?: CVE-2014-8563 is a critical-severity vulnerability in Synacor Zimbra Collaboration Server, classified under OS Command Injection. CVSS score: 9.8/10. Published 2020-01-27.
How severe is CVE-2014-8563?: Critical severity. CVSS v3 base score is 9.8 out of 10.