Zimbra Collaboration

Zimbra Collaboration Suite <10.1.17 OnlyOffice JWT Key Entropy Weakness
CVE-2026-73576 6.3 - Medium - August 13, 2026

In Zimbra Collaboration (ZCS) before 10.1.17, weak cryptographic key generation vulnerability exists in the OnlyOffice integration. The zimbraDocumentEditingJwtSecret is generated using an insecure random number generator, resulting in insufficient entropy. An attacker who obtains a JWT signed with the generated secret may be able to recover the JWT signing secret through offline brute-force, potentially enabling JWT forgery.

Use of Predictable Algorithm in Random Number Generator

Zimbra CSRF in EWS before 10.1.17
CVE-2026-73575 3.1 - Low - August 13, 2026

In Zimbra Collaboration (ZCS) before 10.1.17, a Cross-Site Request Forgery (CSRF) vulnerability exists in the Exchange Web Services (EWS) endpoint of Zimbra Collaboration (ZCS) due to insufficient validation of request content types. An attacker can exploit this vulnerability by causing an authenticated user to submit a crafted request, potentially allowing unauthorized actions to be performed on behalf of the victim.

Session Riding

Zimbra 10.1.17 LFI via fu param in Classic Web Client
CVE-2026-73574 3.1 - Low - August 13, 2026

In Zimbra Collaboration before 10.1.17, a local file inclusion (LFI) vulnerability exists in the Zimbra Classic Web Client due to improper validation of the fu request parameter. An unauthenticated attacker can exploit this vulnerability by supplying a crafted path, potentially allowing unauthorized disclosure of protected files, such as WEB-INF/web.xml, within the web application directory. This occurs in the Forward servlet.

Incorrect Resource Transfer Between Spheres

Zimbra Cb 10.1.17 path traversal in Briefcase edit
CVE-2026-73573 3.1 - Low - August 13, 2026

In Zimbra Collaboration (ZCS) before 10.1.17, a path traversal vulnerability exists in the Zimbra Briefcase document editing functionality due to improper validation of the packages parameter. An authenticated attacker can exploit this vulnerability by supplying a crafted path traversal sequence, potentially allowing unauthorized disclosure of sensitive files within the web application directory.

Path Traversal: '../filedir'

Zimbra Classic Web Client XSS via Attachment Inline Preview (before 10.1.17)
CVE-2026-73572 6.1 - Medium - August 13, 2026

In Zimbra Collaboration (ZCS) before 10.1.17, a stored cross-site scripting (XSS) vulnerability exists in the Zimbra Classic Web Client due to insufficient sanitization of specific attachment content during inline preview. An attacker can send a crafted email containing a malicious attachment that, when previewed by a user, executes arbitrary JavaScript within the victim's browser session. Successful exploitation may allow an attacker to perform unauthorized actions on behalf of the victim user, potentially leading to data exfiltration or unauthorized access to sensitive information.

XSS

Zimbra 10.1.16 & earlier: Auth Bypass via SOAP SaveDraftRequest
CVE-2026-73571 3.1 - Low - August 13, 2026

An authorization bypass vulnerability exists in Zimbra Collaboration (ZCS) before 10.1.17 due to improper authorization validation in delegated email sending functionality. An authenticated attacker can send specially crafted SOAP requests to impersonate another user and send emails without possessing the required delegation or send-as permissions. This occurs in the SaveDraftRequest SOAP handler.

AuthZ

Remote Code Execution via zimbra-snmp SNMP Notifications (pre-10.1.20)
CVE-2026-73570 8.9 - High - August 13, 2026

A remote code execution vulnerability exists in Zimbra Collaboration (ZCS) before 10.1.20 when the optional zimbra-snmp package is installed and SNMP notifications are enabled. Due to improper sanitization of untrusted input during SNMP notification processing, an unauthenticated attacker can send specially crafted SMTP requests that may result in execution of arbitrary operating system commands as the Zimbra user.

Shell injection

Zimbra ZCS 10 <10.0.18 / 10.1 <10.1.13 Classic UI XSS via CSS @import
CVE-2025-66376 7.2 - High - January 05, 2026

Zimbra Collaboration (ZCS) 10 before 10.0.18 and 10.1 before 10.1.13 allows Classic UI stored XSS via Cascading Style Sheets (CSS) @import directives in an HTML e-mail message.

XSS

Zimbra Chat Proxy SSRF in ZCS <10.1.12
CVE-2025-62763 5 - Medium - October 21, 2025

Zimbra Collaboration (ZCS) before 10.1.12 allows SSRF because of the configuration of the chat proxy.

SSRF

CSRF in Zimbra ResetPasswordRequest Enables Unauthorized Password Reset
CVE-2025-54390 6.3 - Medium - September 17, 2025

A Cross-Site Request Forgery (CSRF) vulnerability exists in the ResetPasswordRequest operation of Zimbra Collaboration (ZCS) when the zimbraFeatureResetPasswordStatus attribute is enabled. An attacker can exploit this by tricking an authenticated user into visiting a malicious webpage that silently sends a crafted SOAP request to reset the user's password. The vulnerability stems from a lack of CSRF token validation on the endpoint, allowing password resets without the user's consent.

Session Riding

XSS in Zimbra Collaboration before 10.1; briefcase import metadata
CVE-2024-45515 - July 30, 2025

An issue was discovered in Zimbra Collaboration (ZCS) through 10.1. A Cross-Site Scripting (XSS) vulnerability exists in Zimbra webmail due to insufficient validation of the content type metadata when importing files into the briefcase. Attackers can exploit this issue by crafting a file with manipulated metadata, allowing them to bypass content type checks and execute arbitrary JavaScript within the victim's session.

XSS in Zimbra 9.0-10.1 /h/rest endpoint
CVE-2025-27914 - March 12, 2025

An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0 and 10.1. A Reflected Cross-Site Scripting (XSS) vulnerability exists in the /h/rest endpoint, allowing authenticated attackers to inject and execute arbitrary JavaScript in a victim's session. Exploitation requires a valid auth token and involves a crafted URL with manipulated query parameters that triggers XSS when accessed by a victim.

Stored XSS in Zimbra CWS v9.0-10.1 via Unsanitized iCal
CVE-2025-27915 5.4 - Medium - March 12, 2025

An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0 and 10.1. A stored cross-site scripting (XSS) vulnerability exists in the Classic Web Client due to insufficient sanitization of HTML content in ICS files. When a user views an e-mail message containing a malicious ICS entry, its embedded JavaScript executes via an ontoggle event inside a <details> tag. This allows an attacker to run arbitrary JavaScript within the victim's session, potentially leading to unauthorized actions such as setting e-mail filters to redirect messages to an attacker-controlled address. As a result, an attacker can perform unauthorized actions on the victim's account, including e-mail redirection and data exfiltration.

XSS

SSRF RCE in Zimbra Collaboration 10.1.x (before 10.1.1)
CVE-2024-45518 8.8 - High - October 22, 2024

An issue was discovered in Zimbra Collaboration (ZCS) 10.1.x before 10.1.1, 10.0.x before 10.0.9, 9.0.0 before Patch 41, and 8.8.15 before Patch 46. It allows authenticated users to exploit Server-Side Request Forgery (SSRF) due to improper input sanitization and misconfigured domain whitelisting. This issue permits unauthorized HTTP requests to be sent to internal services, which can lead to Remote Code Execution (RCE) by chaining Command Injection within the internal service. When combined with existing XSS vulnerabilities, this SSRF issue can further facilitate Remote Code Execution (RCE).

SSRF

Zimbra PostJournal unauth exec before 10.1.1
CVE-2024-45519 10 - Critical - October 02, 2024

The postjournal service in Zimbra Collaboration (ZCS) before 8.8.15 Patch 46, 9 before 9.0.0 Patch 41, 10 before 10.0.9, and 10.1 before 10.1.1 sometimes allows unauthenticated users to execute commands.

Shell injection

Zimbra C&S 9.0/10.0 XSS via res param (JS injection)
CVE-2024-33536 5.4 - Medium - August 12, 2024

An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0. The vulnerability occurs due to inadequate input validation of the res parameter, allowing an authenticated attacker to inject and execute arbitrary JavaScript code within the context of another user's browser session. By uploading a malicious JavaScript file, accessible externally, and crafting a URL containing its location in the res parameter, the attacker can exploit this vulnerability. Subsequently, when another user visits the crafted URL, the malicious JavaScript code is executed.

XSS

Zimbra C-10 LFI via packages param in ZCS 9.0/10.0
CVE-2024-33535 7.5 - High - August 12, 2024

An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0. The vulnerability involves unauthenticated local file inclusion (LFI) in a web application, specifically impacting the handling of the packages parameter. Attackers can exploit this flaw to include arbitrary local files without authentication, potentially leading to unauthorized access to sensitive information. The vulnerability is limited to files within a specific directory.

Directory traversal

Zimbra Collab Suite 9.0/10.0 Reflected XSS via packages param
CVE-2024-33533 5.4 - Medium - August 12, 2024

An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0, issue 1 of 2. A reflected cross-site scripting (XSS) vulnerability has been identified in the Zimbra webmail admin interface. This vulnerability occurs due to inadequate input validation of the packages parameter, allowing an authenticated attacker to inject and execute arbitrary JavaScript code within the context of another user's browser session. By uploading a malicious JavaScript file and crafting a URL containing its location in the packages parameter, the attacker can exploit this vulnerability. Subsequently, when another user visits the crafted URL, the malicious JavaScript code is executed.

XSS

Zimbra XSS in CalendarInvite Header (v9.010.0)
CVE-2024-27443 6.1 - Medium - August 12, 2024

An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0. A Cross-Site Scripting (XSS) vulnerability exists in the CalendarInvite feature of the Zimbra webmail classic user interface, because of improper input validation in the handling of the calendar header. An attacker can exploit this via an email message containing a crafted calendar header with an embedded XSS payload. When a victim views this message in the Zimbra webmail classic interface, the payload is executed in the context of the victim's session, potentially leading to execution of arbitrary JavaScript code.

XSS

Zimbra C2 LPE via zmmailboxdmgr (9.0/10.0) arg mishandling
CVE-2024-27442 7.8 - High - August 12, 2024

An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0. The zmmailboxdmgr binary, a component of ZCS, is intended to be executed by the zimbra user with root privileges for specific mailbox operations. However, an attacker can escalate privileges from the zimbra user to root, because of improper handling of input arguments. An attacker can execute arbitrary commands with elevated privileges, leading to local privilege escalation.

Improper Handling of Exceptional Conditions

DOM-based JS Injection in Zimbra Collaboration <9.0.0 Kepler Patch38
CVE-2023-50808 6.1 - Medium - February 13, 2024

Zimbra Collaboration before Kepler 9.0.0 Patch 38 GA allows DOM-based JavaScript injection in the Modern UI.

XSS

Zimbra Collaboration Server 8.8.15/9.0 Account Closure Bypass via IMAP/SMTP
CVE-2023-26562 6.5 - Medium - February 13, 2024

In Zimbra Collaboration (ZCS) 8.8.15 and 9.0, a closed account (with 2FA and generated passwords) can send e-mail messages when configured for Imap/smtp.

AuthZ

Zimbra C 8.8.15/9.0/10.x XSS thru PDF preview JS
CVE-2023-45207 6.1 - Medium - February 13, 2024

An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15, 9.0, and 10.0. An attacker can send a PDF document through mail that contains malicious JavaScript. While previewing this file in webmail in the Chrome browser, the stored XSS payload is executed. (This has been mitigated by sanitising the JavaScript code present in a PDF document.)

XSS

Zimbra Collaboration XSS via help endpoint (8.8.15-10.0)
CVE-2023-45206 6.1 - Medium - February 13, 2024

An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15, 9.0, and 10.0. Through the help document endpoint in webmail, an attacker can inject JavaScript or HTML code that leads to cross-site scripting (XSS). (Adding an adequate message to avoid malicious code will mitigate this issue.)

XSS

Zimbra XSS via maillink causing session theft (ZCS 8.8.15/9.0/10.0)
CVE-2023-48432 6.1 - Medium - February 13, 2024

An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15, 9.0, and 10.0. XSS, with resultant session stealing, can occur via JavaScript code in a link (for a webmail redirection endpoint) within en email message, e.g., if a victim clicks on that link within Zimbra webmail.

XSS

ZCS <10.0.4 XSS allows authenticated mailbox access
CVE-2023-43102 6.1 - Medium - December 07, 2023

An issue was discovered in Zimbra Collaboration (ZCS) before 10.0.4. An XSS issue can be exploited to access the mailbox of an authenticated user. This is also fixed in 8.8.15 Patch 43 and 9.0.0 Patch 36.

XSS

XSS via unsanitized param in Zimbra ZCS before 10.0.4 (8.8.15/9.0.0 fixes)
CVE-2023-43103 6.1 - Medium - December 07, 2023

An XSS issue was discovered in a web endpoint in Zimbra Collaboration (ZCS) before 10.0.4 via an unsanitized parameter. This is also fixed in 8.8.15 Patch 43 and 9.0.0 Patch 36.

XSS

Zimbra Collaboration Server <10.0.3 Account Credential Disclosure
CVE-2023-41106 7.5 - High - December 07, 2023

An issue was discovered in Zimbra Collaboration (ZCS) before 10.0.3. An attacker can gain access to a Zimbra account. This is also fixed in 9.0.0 Patch 35 and 8.8.15 Patch 42.

Zimbra Collaboration Suite v8.8.15/v9.0 sfdc_preauth.jsp Remote Code Exec
CVE-2023-29382 9.8 - Critical - July 06, 2023

An issue in Zimbra Collaboration ZCS v.8.8.15 and v.9.0 allows an attacker to execute arbitrary code via the sfdc_preauth.jsp component.

Zimbra Collaboration Server 8.8.15 Privilege Escalation via Pwd & 2FA
CVE-2023-29381 9.8 - Critical - July 06, 2023

An issue in Zimbra Collaboration (ZCS) v.8.8.15 and v.9.0 allows a remote attacker to escalate privileges and obtain sensitive information via the password and 2FA parameters.

XSS in Zimbra ZCS 8.8.15 /h/autoSaveDraft Allows Remote Auth'd Attacker
CVE-2023-34192 9 - Critical - July 06, 2023

Cross Site Scripting vulnerability in Zimbra ZCS v.8.8.15 allows a remote authenticated attacker to execute arbitrary code via a crafted script to the /h/autoSaveDraft function.

XSS

Zimbra ZCS 8.8.15 File Upload Vulnerability in ClientUploader - RCE
CVE-2023-34193 8.8 - High - July 06, 2023

File Upload vulnerability in Zimbra ZCS 8.8.15 allows an authenticated privileged user to execute arbitrary code and obtain sensitive information via the ClientUploader function.

Unrestricted File Upload

Zimbra CS 9.0/8.8.15 Open Redirect via /preauth
CVE-2023-24030 6.1 - Medium - June 15, 2023

An open redirect vulnerability exists in the /preauth Servlet in Zimbra Collaboration Suite through 9.0 and 8.8.15. To exploit the vulnerability, an attacker would need to have obtained a valid zimbra auth token or a valid preauth token. Once the token is obtained, an attacker could redirect a user to any URL if url sanitisation is bypassed in incoming requests. NOTE: this is similar, but not identical, to CVE-2021-34807.

Open Redirect

Zimbra ZCS 9.0/8.8.15 XSS via /h/ Attr
CVE-2023-24031 6.1 - Medium - June 15, 2023

An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 8.8.15. XSS can occur, via one of attributes of the webmail /h/ endpoint, to execute arbitrary JavaScript code, leading to information disclosure.

XSS

Zimbra 9.0/8.8.15 JVM Arg LPE (Priv Esc)
CVE-2023-24032 7.8 - High - June 15, 2023

In Zimbra Collaboration Suite through 9.0 and 8.8.15, an attacker (who has initial user access to a Zimbra server instance) can execute commands as root by passing one of JVM arguments, leading to local privilege escalation (LPE).

Command Injection

Zimbra Collaboration 9.0 Classic UI XSS via Username Field
CVE-2022-45911 6.1 - Medium - January 06, 2023

An issue was discovered in Zimbra Collaboration (ZCS) 9.0. XSS can occur on the Classic UI login page by injecting arbitrary JavaScript code in the username field. This occurs before the user logs into the system, which means that even if the attacker executes arbitrary JavaScript, they will not get any sensitive information.

XSS

XSS via URL Attributes in Zimbra ZCS 9.0 Webmail
CVE-2022-45913 6.1 - Medium - January 06, 2023

An issue was discovered in Zimbra Collaboration (ZCS) 9.0. XSS can occur via one of attributes in webmail URLs to execute arbitrary JavaScript code, leading to information disclosure.

XSS

ZCS 8.8.15/9.0 RCE via ClientUploader Auth Admin
CVE-2022-45912 7.2 - High - December 05, 2022

An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15 and 9.0. Remote code execution can occur through ClientUploader by an authenticated admin user. An authenticated admin user can upload files through the ClientUploader utility, and traverse to any other directory for remote code execution.

Unrestricted File Upload

ZCS 8.8.15 RefXSS via /h/search?phone in voicemail module
CVE-2022-41350 6.1 - Medium - October 12, 2022

In Zimbra Collaboration Suite (ZCS) 8.8.15, /h/search?action=voicemail&action=listen accepts a phone parameter that is vulnerable to Reflected XSS. This allows executing arbitrary JavaScript on the victim's machine.

XSS

XSS via view param in Zimbra Collaboration Suite 8.8.15 (calendar)
CVE-2022-41351 6.1 - Medium - October 12, 2022

In Zimbra Collaboration Suite (ZCS) 8.8.15, at the URL /h/calendar, one can trigger XSS by adding JavaScript code to the view parameter and changing the value of the uncheck parameter to a string (instead of default value of 10).

XSS

Zimbra ZCS 9.0 XSS via IMG onerror Info Disclosure
CVE-2022-41348 6.1 - Medium - October 12, 2022

An issue was discovered in Zimbra Collaboration (ZCS) 9.0. XSS can occur via the onerror attribute of an IMG element, leading to information disclosure.

XSS

Reflected XSS via /h/compose attachUrl in Zimbra 8.8.15
CVE-2022-41349 6.1 - Medium - October 12, 2022

In Zimbra Collaboration Suite (ZCS) 8.8.15, the URL at /h/compose accepts an attachUrl parameter that is vulnerable to Reflected XSS. This allows executing arbitrary JavaScript on the victim's machine.

XSS

Zimbra Collaboration 8.8.x/9.x: sudo allows zimbra to run NGINX as root
CVE-2022-41347 7.8 - High - September 26, 2022

An issue was discovered in Zimbra Collaboration (ZCS) 8.8.x and 9.x (e.g., 8.8.15). The Sudo configuration permits the zimbra user to execute the NGINX binary as root with arbitrary parameters. As part of its intended functionality, NGINX can load a user-defined configuration file, which includes plugins in the form of .so files, which also execute as root.

Zimbra (ZCS) 8.8.15/9.0 File Upload via amavis Cpio Loophole
CVE-2022-41352 9.8 - Critical - September 26, 2022

An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15 and 9.0. An attacker can upload arbitrary files through amavis via a cpio loophole (extraction to /opt/zimbra/jetty/webapps/zimbra/public) that can lead to incorrect access to any other user accounts. Zimbra recommends pax over cpio. Also, pax is in the prerequisites of Zimbra on Ubuntu; however, pax is no longer part of a default Red Hat installation after RHEL 6 (or CentOS 6). Once pax is installed, amavis automatically prefers it over cpio.

Directory traversal

Zimbra zmslapd root exec via sudo config privilege escalation
CVE-2022-37393 7.8 - High - August 16, 2022

Zimbra's sudo configuration permits the zimbra user to execute the zmslapd binary as root with arbitrary parameters. As part of its intended functionality, zmslapd can load a user-defined configuration file, which includes plugins in the form of .so files, which also execute as root.

X-Forwarded-Host Overrides Host in ZCS 8.8.15/9.0 ProxyServlet - Host Hijack
CVE-2022-37041 7.5 - High - August 12, 2022

An issue was discovered in ProxyServlet.java in the /proxy servlet in Zimbra Collaboration Suite (ZCS) 8.8.15 and 9.0. The value of the X-Forwarded-Host header overwrites the value of the Host header in proxied requests. The value of X-Forwarded-Host header is not checked against the whitelist of hosts that ZCS is allowed to proxy to (the zimbraProxyAllowedDomains setting).

SSRF

Zimbra C7 RCE via mboximport Zip Extraction Auth Bypass (pre-8.8.15/9.0)
CVE-2022-37042 9.8 - Critical - August 12, 2022

Zimbra Collaboration Suite (ZCS) 8.8.15 and 9.0 has mboximport functionality that receives a ZIP archive and extracts files from it. By bypassing authentication (i.e., not having an authtoken), an attacker can upload arbitrary files to the system, leading to directory traversal and remote code execution. NOTE: this issue exists because of an incomplete fix for CVE-2022-27925.

Directory traversal

Zimbra Collab Suite 8.8.15/9.0 CSRF Bypass in Webmail POST
CVE-2022-37043 5.7 - Medium - August 12, 2022

An issue was discovered in the webmail component in Zimbra Collaboration Suite (ZCS) 8.8.15 and 9.0. When using preauth, CSRF tokens are not checked on some POST endpoints. Thus, when an authenticated user views an attacker-controlled page, a request will be sent to the application that appears to be intended. The CSRF token is omitted from the request, but the request still succeeds.

Session Riding

Zimbra 8.8.15 Reflected XSS via /h/search?onload param
CVE-2022-37044 6.1 - Medium - August 12, 2022

In Zimbra Collaboration Suite (ZCS) 8.8.15, the URL at /h/search?action accepts parameters called extra, title, and onload that are partially sanitised and lead to reflected XSS that allows executing arbitrary JavaScript on the victim's machine.

XSS

Zimbra Collaboration Open Source 8.8.15 does not encrypt the initial-login randomly created password (from the "zmprove ca" command)
CVE-2022-32294 9.8 - Critical - July 11, 2022

Zimbra Collaboration Open Source 8.8.15 does not encrypt the initial-login randomly created password (from the "zmprove ca" command). It is visible in cleartext on port UDP 514 (aka the syslog port). NOTE: a third party reports that this cannot be reproduced.

AuthZ