CVE-2026-93647CWE-79cross-site-scripting

CVE-2026-93647

Critical · published September 25, 2026

CVSS v3.1
9.3
EPSS
0%
Percentile
13.0
In the wild
Unconfirmed
What it is

An unauthenticated calendar sender can place active markup in a COUNTER message's RFC From address. Selecting the message in Zimbra Classic triggers stored XSS, allowing the attacker to access mailbox data and act as the victim.

The record
Technical detail
CVSS v3.1
9.3 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.00229 · 13.0th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-09-25T18:17Z
References (1)
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories · [email protected]
EPSS history
Timeline
  • 27 SEP 03:28Z
    EPSS moved — → 0%
    epss
  • 25 SEP 13:58Z
    Zimbra Collaboration Suite Classic Web Client Stored Cross-Site Scripting via Crafted Calendar COUNTER Message From Address
    cvelistv5