EUVD Vulnerability Catalog
EUVD-2026-112942
Severity: MEDIUM
Base Score: 5.3
CVSS Version: 4.0
Vulnerability Description
Zimbra is vulnerable to Stored Cross-Site Scripting (XSS) via the From email header during HTML reply composition in Classic UI. Due to insufficient sanitization of the From header value, a remote attacker can send a crafted email containing a malicious From header with an embedded JavaScript payload. When the victim opens the message in Classic UI and clicks Reply while composing in HTML mode with reply headers disabled, the unsanitized From header content is rendered as HTML and the JavaScript payload executes in the victim's browser, potentially allowing the attacker to steal session information or perform actions on behalf of the victim. This issue was fixed in version 10.1.21
CVSS Vector Analysis
Below is the complete, human-readable breakdown of the CVSS metric string: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
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Attack Vector (AV): Network
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Attack Complexity (AC): Low
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Attack Requirements (AT): None
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Privileges Required (PR): None
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User Interaction (UI): Passive
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Vulnerability Confidentiality Impact (VC): None
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Vulnerability Integrity Impact (VI): None
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Vulnerability Availability Impact (VA): None
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Subsequent Confidentiality Impact (SC): Low
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Subsequent Integrity Impact (SI): Low
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Subsequent Availability Impact (SA): None
Affected Vendors & Systems
Vendor
Synacor
References & Advisory Links
Metadata Profile
Database Authority
European Union Agency for Cybersecurity (ENISA) EUVD
Assigner
CERT-PL
EPSS Probability
0
Known Aliases
GHSA-rprc-q5mj-4mcw
CVE-2026-66912
Published On
2026-10-29
Last Updated
2026-10-29