What is CVE-2023-34192?

CVE-2023-34192 is a critical-severity vulnerability in Synacor Zimbra Collaboration Suite, classified under Cross-site Scripting. CVSS score: 9.0/10. Published 2023-07-06.

How severe is CVE-2023-34192?

Critical severity. CVSS v3 base score is 9.0 out of 10.

Is CVE-2023-34192 known to be exploited?

Yes. CVE-2023-34192 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-02-25), indicating it is being actively exploited. 4 public proof-of-concept repositories are indexed.

XSS in Synacor Zimbra Collaboration Suite

CVE-2023-34192

Cross Site Scripting vulnerability in Zimbra ZCS v.8.8.15 allows a remote authenticated attacker to execute arbitrary code via a crafted script to the /h/autoSaveDraft function.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2023-07-06 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.773 (99.6th percentile), scored 2026-10-17.

High probability of exploitation in the next 30 days — patch promptly. 100th percentile — 99.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.773 · newest: 0.773 · change: 0.000

Affected products

Synacor Zimbra Collaboration Suite — versions 8.8.15

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2025-02-25. 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: 2025-03-18.

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.

Public proof-of-concept exploits

References

wiki.zimbra.com/wiki/Zimbra_Security_Advisories (Vendor Advisory)
wiki.zimbra.com/wiki/Security_Center (Release Notes, Vendor Advisory)
wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy (Not Applicable)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2023-34192?: CVE-2023-34192 is a critical-severity vulnerability in Synacor Zimbra Collaboration Suite, classified under Cross-site Scripting. CVSS score: 9.0/10. Published 2023-07-06.
How severe is CVE-2023-34192?: Critical severity. CVSS v3 base score is 9.0 out of 10.
Is CVE-2023-34192 known to be exploited?: Yes. CVE-2023-34192 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-02-25), indicating it is being actively exploited. 4 public proof-of-concept repositories are indexed.