Home/CVE/An issue was discovered in Zimbra Collaboration (ZCS) 10.0 and 10.1. An XML External Entity (XXE) vulnerability exists i
CVE

CVE-2026-33371

An issue was discovered in Zimbra Collaboration (ZCS) 10.0 and 10.1. An XML External Entity (XXE) vulnerability exists i

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.

MEDIUM · CVSS 4.3 EPSS 0.00062
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-611Improper Restriction of XML External Entity Reference
▤

Affected Products & Versions

1
synacor zimbra collaboration suite>= 10.0.0 and < 10.1.16
▣

Scoring & Timeline

4.3
MEDIUM · CVSS v3.1 · cve@mitre.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD20 Mar 2026 · 02:16 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
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References & Sources

4
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://wiki.zimbra.com/wiki/Security_CenterRelease NotesVendor Advisory
https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.16#Security_FixesRelease Notes
https://wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_PolicyProduct
https://wiki.zimbra.com/wiki/Zimbra_Security_AdvisoriesVendor Advisory
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