Medium severity · published Mar 20, 2026
CVE-2026-33371
An issue was discovered in Zimbra Collaboration (ZCS) 10.0 and 10.1
4.3
CVSS
0.2%
EPSS
No
On KEV
Description
An issue was discovered in Zimbra Collaboration (ZCS) 10.0 and 10.1. An XML External Entity (XXE) vulnerability exists in the Zimbra Exchange Web Services (EWS) SOAP interface due to improper handling of XML input. An authenticated attacker can submit crafted XML data that is processed by an XML parser with external entity resolution enabled. Successful exploitation may allow disclosure of sensitive local files from the server.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 15% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ZC
Zimbra Collaboration Suite · Synacor
10.0.0 before 10.1.16 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33371
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-33371
Release Notes
https://wiki.zimbra.com/wiki/Security_Center
Release Notes
https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.16#Security_Fixes
Product
https://wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy
Vendor Advisory
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
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