CVE-2025-27915 on CISA KEV

An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0 and 10.1. A stored cross-site scripting (XSS) vulnerability exists in the Classic Web Client due to insufficient sanitization of HTML content in ICS files. When a user views an e-mail message containing a maliciou

01What CISA says about this vulnerability

An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0 and 10.1. A stored cross-site scripting (XSS) vulnerability exists in the Classic Web Client due to insufficient sanitization of HTML content in ICS files. When a user views an e-mail message containing a malicious ICS entry, its embedded JavaScript executes via an ontoggle event inside a <details> tag. This allows an attacker to…

02Required action — verbatim from CISA

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

03Notes & references

• wiki.zimbra.com — https://wiki.zimbra.com/wiki/Security_Center
• wiki.zimbra.com — https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.5#Security_Fixes
• wiki.zimbra.com — https://wiki.zimbra.com/wiki/Zimbra_Releases/10.0.13#Security_Fixes
• wiki.zimbra.com — https://wiki.zimbra.com/wiki/Zimbra_Releases/9.0.0/P44#Security_Fixes

04SARA's analyst layer — why this matters

This vulnerability is currently on the CISA KEV list, which CISA only adds CVEs to when there is reliable evidence of active exploitation in the wild. For federal civilian agencies, BOD 22-01 requires remediation by the due date above. For everyone else, KEV is the strongest "patch immediately" signal you can get from public threat intel.

05Affected products (summary)

Vendor	Product	Versions
n	a / n/a	n/a

06Detection

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