# CVE-2018-6882: Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting (XSS) Vulnerability

- Exploited (CISA KEV): yes, added 2022-04-19, known ransomware use
- Published: 2018-03-27
- CVSS: 6.1 MEDIUM (v3.1)
- EPSS: 29.8% (98th percentile)
- CWE: CWE-79

Cross-site scripting (XSS) vulnerability in the ZmMailMsgView.getAttachmentLinkHtml function in Zimbra Collaboration Suite (ZCS) before 8.7 Patch 1 and 8.8.x before 8.8.7 might allow remote attackers to inject arbitrary web script or HTML via a Content-Location header in an email attachment.

## Edge WAF coverage (claimed by vendors, not measured)

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | Before feed history | — | — |
| AWS | Before feed history | — | — |
| Microsoft Azure | No public claim | — | — |
| Google Cloud | Before feed history | — | — |
| Fastly | Before feed history | — | — |
| F5 | Before feed history | — | — |
| Akamai | No public source | — | — |
| OWASP CRS | Before feed history | — | — |

## Our test (measured)

- OWASP Core Rule Set 4.25.0, paranoia level 1, anomaly threshold 5, default CRS settings: passed (0 of 3 requests blocked), template CVE-2018-6882, 2026-11-02
- OWASP Core Rule Set 4.25.0, paranoia level 2, anomaly threshold 5, default CRS settings: partial (1 of 3 requests blocked), template CVE-2018-6882, 2026-11-02

"No public claim" means no vendor statement names this CVE; "Before feed history" means the CVE is older than the vendor feed. In both cases generic rules may still block it.

HTML: https://cve.vigilbase.com/cve/CVE-2018-6882 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2018-6882