Zimbra Collaboration Suite up to 10.1.20 COUNTER Message cross site scripting

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Zimbra Collaboration Suite up to 10.1.20. This issue affects some unknown processing of the component COUNTER Message Handler. Performing a manipulation results in cross site scripting. This vulnerability is identified as CVE-2026-93647. The attack can be initiated remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Zimbra Collaboration Suite up to 10.1.20. It has been classified as problematic. This affects an unknown functionality of the component COUNTER Message Handler. The manipulation with an unknown input leads to a cross site scripting vulnerability. CWE is classifying the issue as CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. This is going to have an impact on integrity. The summary by CVE is:

An unauthenticated calendar sender can place active markup in a COUNTER message's RFC From address. Selecting the message in Zimbra Classic triggers stored XSS, allowing the attacker to access mailbox data and act as the victim.

It is possible to read the advisory at wiki.zimbra.com. This vulnerability is uniquely identified as CVE-2026-93647 since 09/18/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

Upgrading to version 10.1.21 eliminates this vulnerability.

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Productinfo

Type

• Groupware Software

Vendor

• Zimbra

Name

• Collaboration Suite

Version

• 10.1.0
• 10.1.1
• 10.1.2
• 10.1.3
• 10.1.4
• 10.1.5
• 10.1.6
• 10.1.7
• 10.1.8
• 10.1.9
• 10.1.10
• 10.1.11
• 10.1.12
• 10.1.13
• 10.1.14
• 10.1.15
• 10.1.16
• 10.1.17
• 10.1.18
• 10.1.19
• 10.1.20

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CPE 2.2info

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