Critical severity · published Sep 25, 2026
CVE-2026-93643
Zimbra Collaboration Suite OnlyOffice Integration Path Traversal Leading to Remote Code Execution via Unauthenticated /downloadas Request
9.8
CVSS
1%
EPSS
No
On KEV
Description
When OnlyOffice/Document Editing is available, an unauthenticated remote attacker with access to an existing supported public Briefcase document can abuse unsigned save fields to perform path-traversal writes and execute commands as zimbra.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.0% · higher than 61% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ZC
Zimbra Collaboration Suite (ZCS) · Zimbra
before 10.1.21 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-93643
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-93643
wiki.zimbra.com
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
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