XSS in Zimbra Collaboration Suite (Zcs)

CVE-2026-93641

An unauthenticated sender can forge a share notification that triggers stored XSS when a signed-in Zimbra Classic recipient clicks Accept Share, allowing the attacker to access mailbox data and act as the victim.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.3 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.003 (19.8th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 19.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-93641: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-93641?
CVE-2026-93641 is a critical-severity vulnerability in Zimbra Collaboration Suite (Zcs), classified under Cross-site Scripting. CVSS score: 9.3/10. Published 2026-09-25.
How severe is CVE-2026-93641?
Critical severity. CVSS v3 base score is 9.3 out of 10.