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.

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

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.

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.

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.

An issue was discovered in the Calendar feature in Zimbra Collaboration Suite 8.8.x before 8.8.15 patch 30 (update 1), as exploited in the wild starting in December 2021. An attacker could place HTML containing executable JavaScript inside element attributes. This markup becomes unescaped, causing arbitrary markup to be injected into the document.

An issue was discovered in ProxyServlet.java in the /proxy servlet in Zimbra Collaboration Suite 8.8 before 8.8.15 Patch 23 and 9.x before 9.0.0 Patch 16. The value of the X-Host header overwrites the value of the Host header in proxied requests. The value of X-Host header is not checked against the whitelist of hosts Zimbra is allowed to proxy to (the zimbraProxyAllowedDomains setting).

An issue was discovered in ZmMailMsgView.js in the Calendar Invite component in Zimbra Collaboration Suite 8.8.x before 8.8.15 Patch 23. An attacker could place HTML containing executable JavaScript inside element attributes. This markup becomes unescaped, causing arbitrary markup to be injected into the document.

An issue was discovered in Zimbra Collaboration Suite 8.8 before 8.8.15 Patch 23 and 9.0 before 9.0.0 Patch 16. An XSS vulnerability exists in the login component of Zimbra Web Client, in which an attacker can execute arbitrary JavaScript by adding executable JavaScript to the loginErrorCode parameter of the login url.

An open redirect vulnerability exists in the /preauth Servlet in Zimbra Collaboration Suite through 9.0. 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 via isredirect=1&redirectURL= in conjunction with the token data (e.g., a valid authtoken= value).

In Zimbra Collaboration Suite Network Edition versions < 9.0.0 P10 and 8.8.15 P17, there exists an XXE vulnerability in the saml consumer store extension, which is vulnerable to XXE attacks. This has been fixed in Zimbra Collaboration Suite Network edition 9.0.0 Patch 10 and 8.8.15 Patch 17.