CVE-2026-93639

Zimbra Collaboration Suite Missing Authorization in ConfigureZimlet Enables Delegated Administrator Privilege Escalation

Published Oct 23, 2026 CVSS 3.1 · 8.7 High EPSS < 1% KEV · Not listed
Description
A missing authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows a delegated administrator with no explicit administrative grants to overwrite global Zimlet configuration through ConfigureZimletRequest. The uploaded configuration can also add an attacker-controlled domain to the proxy allowlist of the default class of service. If a signed-in user in that class opens a crafted /service/proxy URL, Zimbra serves attacker-controlled HTML under its own origin. The resulting JavaScript can read mailbox data and perform authenticated actions as the victim. Exploitation requires a delegated-administrator account and access to the admin SOAP service; the browser compromise additionally requires the victim to open the crafted URL. ZCS 10.1.16 and 10.1.20 are affected.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Zimbra
Zimbra zimbra Collaboration Suite
Vendors & Products Zimbra
Zimbra zimbra Collaboration Suite
Type Values Removed Values Added
Description A missing authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows a delegated administrator with no explicit administrative grants to overwrite global Zimlet configuration through ConfigureZimletRequest. The uploaded configuration can also add an attacker-controlled domain to the proxy allowlist of the default class of service. If a signed-in user in that class opens a crafted /service/proxy URL, Zimbra serves attacker-controlled HTML under its own origin. The resulting JavaScript can read mailbox data and perform authenticated actions as the victim. Exploitation requires a delegated-administrator account and access to the admin SOAP service; the browser compromise additionally requires the victim to open the crafted URL. ZCS 10.1.16 and 10.1.20 are affected.
Title Zimbra Collaboration Suite Missing Authorization in ConfigureZimlet Enables Delegated Administrator Privilege Escalation
Weaknesses CWE-862
References
Metrics cvssV3_1

{'score': 8.7, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
rapid7
Published
Updated
Oct 28, 2026, 7:49 PM
Reserved
Sep 18, 2026, 12:22 PM
Status
Undergoing Analysis
Published
Oct 23, 2026, 2:17 PM
Modified
Oct 28, 2026, 8:18 PM