A mailbox quota-accounting vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to consume another user’s mailbox quota by repeatedly sharing and revoking a document. Creation of the recipient’s shared-file record charges the document size to mailbox-wide usage. Revocation deletes the record and reverses its folder counters without reversing the mailbox-wide charge. Repeated normal share notifications therefore accumulate quota usage after the visible records are gone. On accounts with a finite quota, this can prevent incoming mail and other size-increasing operations without recipient interaction. The issue affects ZCS 10.1.16 and 10.1.20.

An SMTP command injection vulnerability in the data-source testing functionality of Zimbra Collaboration Suite (ZCS) allows an ordinary authenticated user with account options enabled to inject CR/LF into the emailAddress inserted into an SMTP envelope command by a JSON SOAP request. After a successful preliminary POP3 or IMAP login, Zimbra sends the injected commands to the selected SMTP service. If that service accepts the pipelined transaction, the attacker can submit mail with attacker-selected recipients, headers and body content without victim interaction. The vulnerable command-construction path is present in ZCS 10.1.16 and 10.1.20.

A reflected cross-site scripting vulnerability in the login page of Zimbra Collaboration Suite (ZCS) allows an unauthenticated attacker to execute JavaScript through the zrememberme parameter. A crafted relogin URL selects a two-factor error display that inserts the parameter into a hidden input attribute without HTML encoding. A victim who opens the URL receives attacker-controlled script and page content under the legitimate Zimbra origin, allowing credential capture through a replacement login form. The relogin path logs out an existing session before rendering the payload, so the demonstrated attack does not inherit that session's mailbox access. ZCS 10.1.16 and 10.1.17 are affected.

A cross-account authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to insert forged shared-file records into another user's mailbox through FileSharedWithMeRequest. The request bypasses delegated-account authorization and accepts attacker-selected file metadata, owner identifiers and declared sizes without validating a corresponding document share. An attacker can plant entries attributed to another real local account without that account sharing a document. No victim interaction is required. ZCS 10.1.16 and 10.1.20 are affected.

A CSS sanitization vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user with Briefcase access to publish a document that displays attacker-controlled content under the Zimbra origin. When processing a stylesheet containing non-ASCII characters, DefangFilter appends the final ASCII segment without sanitizing it. HTML stored as application/x-zimbra-doc can therefore retain CSS URL references that the normal sanitizer removes. An attacker can share a crafted document that loads external resources and displays a credential-collection form using Zimbra's own visual assets. Exploitation requires the victim to open the document in a browser that renders the content type inline; credential theft additionally requires form submission. ZCS 10.1.16 and 10.1.20 are affected.

An organizer authentication vulnerability in Zimbra Collaboration Suite (ZCS) allows an unauthenticated email sender to insert calendar invitations attributed to another user. The email delivery path permits external invitations but does not verify that the message sender is authorized to use the iCalendar ORGANIZER identity. When automatic invitation insertion is enabled, a crafted REQUEST component creates an event containing attacker-selected meeting details and reminders under a forged organizer without recipient interaction. No corresponding event is created in the claimed organizer's calendar. ZCS 10.1.16 and 10.1.21 are affected.

An authentication rate-limit bypass in Zimbra Collaboration Suite 10.1.0 through 10.1.21 allows unauthenticated attackers to make repeated password guesses through GraphQL without incrementing Zimbra’s source-IP failure counter. GraphQL aliases allow multiple authentication attempts in one HTTP request.

LDAP filter injection in Zimbra Collaboration Suite 10.1.0 through 10.1.21 allows unauthenticated attackers to alter external LDAP search filters. On domains using search-filter authentication and lazy provisioning, this creates a password oracle for external directory users. Authenticated S/MIME lookups can also return certificates and identity data for unintended directory entries.

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.

An issue was discovered in Zimbra Collaboration (ZCS) 9.0.0 before Patch 43, 10.0.x before 10.0.12, 10.1.x before 10.1.4, and 8.8.15 before Patch 47. A Cross-Site Scripting (XSS) vulnerability in the Zimbra Classic UI allows attackers to execute arbitrary JavaScript within the user's session, potentially leading to unauthorized access to sensitive information. This issue arises from insufficient sanitization of HTML content, including malformed <img> tags with embedded JavaScript. The vulnerability is triggered when a user views a specially crafted email in the Classic UI, requiring no additional user interaction.

In Zimbra Collaboration (ZCS) 9.0 through 10.1, a Cross-Site Request Forgery (CSRF) vulnerability exists in the GraphQL endpoint (/service/extension/graphql) of Zimbra webmail due to a lack of CSRF token validation. This allows attackers to perform unauthorized GraphQL operations, such as modifying contacts, changing account settings, and accessing sensitive user data when an authenticated user visits a malicious website.

An issue was discovered in the Webmail Classic UI in Zimbra Collaboration (ZCS) 9.0 and 10.0 and 10.1. A Local File Inclusion (LFI) vulnerability exists in the /h/rest endpoint, allowing authenticated remote attackers to include and access sensitive files in the WebRoot directory. Exploitation requires a valid auth token and involves crafting a malicious request targeting specific file paths.

This vulnerability allows remote attackers to disclose sensitive information on affected installations of Zimbra. User interaction is required to exploit this vulnerability in that the target must open a malicious email message. The specific flaw exists within the implementation of the graphql endpoint. The issue results from the lack of proper protections against cross-site request forgery (CSRF) attacks. An attacker can leverage this vulnerability to disclose information in the context of the target email account.

An issue was discovered in webmail in Zimbra Collaboration (ZCS) through 10.1. An attacker can exploit this vulnerability by creating a folder in the Briefcase module with a malicious payload and sharing it with a victim. When the victim interacts with the folder share notification, the malicious script executes in their browser. This stored Cross-Site Scripting (XSS) vulnerability can lead to unauthorized actions within the victim's session.

An issue was discovered in Zimbra Collaboration (ZCS) through v10.1. A Cross-Site Scripting (XSS) vulnerability exists in one of the endpoints of Zimbra Webmail due to insufficient sanitization of the packages parameter. Attackers can bypass the existing checks by using encoded characters, allowing the injection and execution of arbitrary JavaScript within a victim's session.

An issue was discovered in Zimbra Collaboration (ZCS) through 10.1. A Cross-Site Scripting (XSS) vulnerability in the /h/rest endpoint of the Zimbra webmail and admin panel interfaces allows attackers to execute arbitrary JavaScript in the victim's session. This issue is caused by improper sanitization of user input, leading to potential compromise of sensitive information. Exploitation requires user interaction to access the malicious URL.

An issue was discovered in Zimbra Collaboration (ZCS) through 10.1. A stored Cross-Site Scripting (XSS) vulnerability exists in the /modern/contacts/print endpoint of Zimbra webmail. This allows an attacker to inject and execute arbitrary JavaScript code in the context of the victim's browser when a crafted vCard (VCF) file is processed and printed. This could lead to unauthorized actions within the victim's session.

In Zimbra Collaboration (ZCS) 9.0 and 10.0, a vulnerability in the Webmail Modern UI allows execution of stored Cross-Site Scripting (XSS) payloads. An attacker with administrative access to the Zimbra Administration Panel can inject malicious JavaScript code while configuring an email account. This injected code is stored on the server and executed in the context of the victim's browser when interacting with specific elements in the web interface. (The vulnerability can be mitigated by properly sanitizing input parameters to prevent the injection of malicious code.)

An issue was discovered in Zimbra Collaboration (ZCS) through 10.1. A reflected Cross-Site Scripting (XSS) issue exists through the Briefcase module due to improper sanitization of file content by the OnlyOffice formatter. This occurs when the victim opens a crafted URL pointing to a shared folder containing a malicious file uploaded by the attacker. The vulnerability allows the attacker to execute arbitrary JavaScript in the context of the victim's session.

An issue was discovered in Zimbra Collaboration (ZCS) through 10.0. Zimbra Webmail (Modern UI) is vulnerable to a stored Cross-Site Scripting (XSS) attack due to improper sanitization of user input. This allows an attacker to inject malicious code into specific fields of an e-mail message. When the victim adds the attacker to their contacts, the malicious code is stored and executed when viewing the contact list. This can lead to unauthorized actions such as arbitrary mail sending, mailbox exfiltration, profile picture alteration, and other malicious actions. Proper sanitization and escaping of input fields are necessary to mitigate this vulnerability.

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).

This vulnerability allows remote attackers to disclose sensitive information on affected installations of Zimbra. User interaction is required to exploit this vulnerability in that the target must open a malicious email message. The specific flaw exists within the implementation of the graphql endpoint. The issue results from the lack of proper protections against cross-site request forgery (CSRF) attacks. An attacker can leverage this vulnerability to disclose information in the context of the target email account.

This vulnerability allows remote attackers to disclose sensitive information on affected installations of Zimbra. User interaction is required to exploit this vulnerability in that the target must open a malicious email message. The specific flaw exists within the implementation of the graphql endpoint. The issue results from the lack of proper protections against cross-site request forgery (CSRF) attacks. An attacker can leverage this vulnerability to disclose information in the context of the target email account.

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.

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.

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.

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.