CVE-2026-34718 Details
Description
Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.1 and 6.5.4, the HTML sanitizer for ticket articles was missing proper sanitization of data: ... URI schemes, resulting in storing such malicious content in the database of the Zammad instance. The Zammad GUI is rendering this content, due to applied CSP rules no harm was done by e.g., clicking such a link. This vulnerability is fixed in 7.0.1 and 6.5.4.
A vulnerability exists in Zammad, a web-based open-source helpdesk and customer support system, in versions prior to 7.0.1 and 6.5.4. The issue arises from the HTML sanitizer for ticket articles, which failed to properly sanitize 'data: ...' URI schemes. This oversight allowed malicious content to be stored in the database of affected Zammad instances. Although the Zammad GUI renders this content, applied Content Security Policy (CSP) rules prevented any harm from, for example, clicking such a link.
Users can upgrade to Zammad versions 7.0.1 or 6.5.4 to address this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Apr 8, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/zammad/zammad/security/advisories/GHSA-c2cf-9fc7-jhf3 | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-80 | Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS) | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| zammad zammad | < 6.5.4 7.0.0 |
CPE
Remediation
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Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 24, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Apr 17, 2026 | Initial Analysis | [email protected] |
| Apr 8, 2026 | New CVE Received | [email protected] |