Medium severity · published Oct 8, 2026
CVE-2026-10631
Zimbra Collaboration Suite EWS Extension Authorization Bypass via Crafted Composite Folder/Item Identifier
6.5
CVSS
0.3%
EPSS
No
On KEV
Description
An authorization bypass in the EWS FindItem handler of Zimbra Collaboration Suite 10.1.0 through 10.1.19 allows an authenticated user with EWS enabled to read complete mailbox items, including raw MIME and attachments, from arbitrary local accounts without a share or delegation grant.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 21% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CO
Collaboration · Zimbra
before 10.1.20 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-10631
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-10631
vendor-advisory
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
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