What is CVE-2022-27924?

CVE-2022-27924 is a high-severity vulnerability in Synacor Zimbra Collaboration Suite, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 7.5/10. Published 2022-04-21.

How severe is CVE-2022-27924?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2022-27924 known to be exploited?

Yes. CVE-2022-27924 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-08-04), indicating it is being actively exploited. 7 public proof-of-concept repositories are indexed.

Vulnerability in Synacor Zimbra Collaboration Suite

CVE-2022-27924

Zimbra Collaboration (aka ZCS) 8.8.15 and 9.0 allows an unauthenticated attacker to inject arbitrary memcache commands into a targeted instance. These memcache commands becomes unescaped, causing an overwrite of arbitrary cached entries.

Published 2022-04-21 · last modified 2026-10-02.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.939 (99.8th percentile), scored 2026-10-15.

High probability of exploitation in the next 30 days — patch promptly. 100th percentile — 99.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.854 · newest: 0.939 · change: +0.085

Affected products

Synacor Zimbra Collaboration Suite — versions 8.8.15, 9.0.0

Weakness classification (CWE)

CWE-74 — Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection)

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2022-08-04. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2022-08-25.

Required action: Apply updates per vendor instructions.

Known ransomware campaign use: yes.

Public proof-of-concept exploits

References

wiki.zimbra.com/wiki/Zimbra_Security_Advisories (Vendor Advisory)
wiki.zimbra.com/wiki/Security_Center (Vendor Advisory)
wiki.zimbra.com/wiki/Zimbra_Releases/9.0.0/P24 (Release Notes, Vendor Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2022-27924?: CVE-2022-27924 is a high-severity vulnerability in Synacor Zimbra Collaboration Suite, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 7.5/10. Published 2022-04-21.
How severe is CVE-2022-27924?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2022-27924 known to be exploited?: Yes. CVE-2022-27924 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-08-04), indicating it is being actively exploited. 7 public proof-of-concept repositories are indexed.