CVE-2022-27926: in the CISA KEV catalogue
Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting (XSS) Vulnerability. CISA added CVE-2022-27926 to the Known Exploited Vulnerabilities catalogue on 2023-04-03 with a default due date of 2023-04-24. Known ransomware campaign use: Unknown. Forensic triage flag: No.
Synacor Zimbra Collaboration Suite (ZCS) contains a cross-site scripting vulnerability by allowing an endpoint URL to accept parameters without sanitizing. (CISA description)
- Vendor / product
- Synacor Zimbra Collaboration Suite (ZCS)
- CWE
- CWE-79, CWE-138
- CISA required action
- Apply updates per vendor instructions.
- EPSS
- 18%, percentile 97 (scored 2026-11-03)
EPSS puts about 18 in 100 odds (18%) on exploitation activity being observed in the next 30 days. Its score is higher than or equal to that of 97% of scored CVEs. This is a model estimate about exploitation anywhere, not about your environment.
Vendor and reference links (from CISA)
Your own deadline under CISA BOD 26-04 depends on exposure, automatability and technical impact: work it out with the BOD 26-04 calculator.
Frequently asked questions
Is CVE-2022-27926 in the CISA KEV catalogue?
Yes. CISA added CVE-2022-27926 (Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting (XSS) Vulnerability) to the Known Exploited Vulnerabilities catalogue on 2023-04-03. CISA's default due date for it is 2023-04-24.
Is CVE-2022-27926 used in ransomware attacks?
CISA marks known ransomware campaign use as Unknown for CVE-2022-27926. That means CISA lacks confirmation, not that ransomware groups do not use it.
What should I do about CVE-2022-27926?
CISA's required action: Apply updates per vendor instructions.
Sources
- CISA, Known Exploited Vulnerabilities Catalog (accessed 2026-11-03)
- FIRST, Exploit Prediction Scoring System (EPSS) (EPSS by FIRST; scores generated by Empirical Security)
- NVD record for CVE-2022-27926