Is CVE-2026-33371 in the CISA KEV catalog?

No. CVE-2026-33371 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-33371?

CVE-2026-33371 has a CVSS v3 base score of 4.3 (MEDIUM).

What is the EPSS score for CVE-2026-33371?

CVE-2026-33371 has an EPSS score of 0.23% (14th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-33371?

Upgrade zimbra collaboration suite to 10.1.16 or later.

CVE & CISA-KEV Catalog

CVE-2026-33371

MEDIUM

4.3

CVSS v3

NVD

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.

CWE-611XML External Entity (XXE)

How to fix

Remediation Available

zimbra collaboration suiteNVD

Affected:>= 10.0.0, < 10.1.16Fixed in:10.1.16CVE-2026-33371derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityNone

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Exploit Intelligence

0.23%probability of exploitation in 30 days

14thpercentile

Low risk: more likely to be exploited than 14% of all known CVEs.

References

Vendor Advisory2

Release Notes1

wiki.zimbra.com

Product1

wiki.zimbra.com

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-01.