CVE-2015-7609
Description
Zimbra Mail Client 8.6 before 8.6.0 Patch 5 is vulnerable to XSS via improperly sanitized email body content and error/warning dialogs.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Zimbra Mail Client 8.6 before 8.6.0 Patch 5 is vulnerable to XSS via improperly sanitized email body content and error/warning dialogs.
Vulnerability
A cross-site scripting (XSS) vulnerability exists in Synacor Zimbra Mail Client version 8.6 prior to 8.6.0 Patch 5 [2][3]. The flaw originates from insufficient sanitization of email body content and error/warning dialog messages, allowing attackers to inject arbitrary JavaScript or HTML [1]. Affected versions include all Zimbra Collaborative Suite (ZCS) 8.6.0 releases before the Patch 5 update [2][3].
Exploitation
An attacker can exploit this vulnerability by sending a specially crafted email containing malicious script code in the body text or by triggering an error/warning dialog that includes attacker-controlled input [2][3]. The email content is rendered in the victim's browser without proper sanitization, leading to script execution in the context of the Zimbra web client session [3]. No authentication is required for the initial delivery, but the victim must open the malicious email or trigger the dialog while logged into Zimbra [2][3].
Impact
Successful exploitation allows the attacker to execute arbitrary JavaScript in the context of the victim's Zimbra session [2][3]. This can lead to session hijacking, unauthorized access to emails and contacts, or other actions the victim can perform in the Zimbra web interface [2][3]. The vulnerability has a CVSS score of 2.6, indicating low overall severity, but the impact can vary depending on the victim's privileges [2].
Mitigation
The vulnerability is fixed in Zimbra Collaboration Suite (ZCS) version 8.6.0 Patch 5, released in late 2015 [2][3]. Administrators should upgrade to Patch 5 or later (e.g., 8.7.0) to remediate the issue [1][2][3]. No workarounds are documented, but avoiding opening emails from untrusted sources reduces risk. The CVE is not listed in CISA's Known Exploited Vulnerabilities (KEV) catalog.
AI Insight generated on May 26, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.
Affected products
2- Synacor/Zimbra Mail Clientdescription
- Range: <8.6.0 Patch 5
Patches
0No patches discovered yet.
Vulnerability mechanics
Root cause
"The Zimbra Mail Client fails to properly sanitize HTML content within email bodies and error/warning dialogs, allowing for the injection of malicious scripts."
Attack vector
An attacker can craft an email containing malicious HTML and script content. When this email is viewed by a user within the Zimbra Mail Client, the embedded scripts are executed in the user's browser context. This vulnerability affects the error/warning dialogs and the email body content, enabling cross-site scripting attacks [ref_id=1].
What the fix does
The advisory indicates that patches fix critical security vulnerabilities related to stored cross-site scripting in the Zimbra Classic Web Client by strengthening input sanitization and enhancing security [ref_id=1]. While specific code changes are not detailed, the general approach involves ensuring that user-supplied HTML content is properly escaped or filtered before being rendered.
Preconditions
- inputThe attacker must be able to send an email to a user of the affected Zimbra version.
Generated on Jun 3, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.
References
5- bugzilla.zimbra.com/show_bug.cgimitrex_refsource_MISC
- bugzilla.zimbra.com/show_bug.cgimitrex_refsource_MISC
- wiki.zimbra.com/wiki/Security_Centermitrex_refsource_MISC
- www.fortiguard.com/zeroday/FG-VD-15-080mitrex_refsource_MISC
- www.fortiguard.com/zeroday/FG-VD-15-081mitrex_refsource_MISC
News mentions
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