CVE-2026-93647 (GCVE-0-2026-93647)

Vulnerability from cvelistv5 – Published: 2026-09-25 13:58 – Updated: 2026-09-26 03:55
VLAI
Title
Zimbra Collaboration Suite Classic Web Client Stored Cross-Site Scripting via Crafted Calendar COUNTER Message From Address
Summary
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.
Severity
9.3 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-25 00:00 UTC
CWE
  • CWE-79 - Improper neutralization of input during web page generation ('cross-site scripting')
Assigner
References
Impacted products
Vendor Product Version CPE status
Zimbra Zimbra Collaboration Suite (ZCS) Affected: 0 , < 10.1.21 (semver)
guessed Create a notification for this product.
Date Public
2026-09-25 13:53
Credits
Jonah Burgess (CryptoCat), Senior Security Researcher, Rapid7
Show details on NVD website
To clipboard 

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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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