Loading vulnerabilities…
Loading vulnerabilities…
CVE-2025-27915
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 run arbitrary JavaScript within the victim's session, potentially leading to unauthorized actions such as setting e-mail filters to redirect messages to an attacker-controlled address. As a result, an attacker can perform unauthorized actions on the victim's account, including e-mail redirection and data exfiltration.
This record: live connection— last retrieved: 24 September 2026 at 05:28.
Vendor
SynacorProduct
Zimbra Collaboration Suite (ZCS)up to version cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:*
Published
12 March 2025
Last modified
17 June 2026
Taken directly from NVD, CISA or the vendor — sometimes in English, unchanged from the source.
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 run arbitrary JavaScript within the victim's session, potentially leading to unauthorized actions such as setting e-mail filters to redirect messages to an attacker-controlled address. As a result, an attacker can perform unauthorized actions on the victim's account, including e-mail redirection and data exfiltration.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Attack vector
NETWORK
Privileges required
LOW
User interaction
REQUIRED
Confidentiality
Limited
Integrity
Limited
Availability
None
Probability of exploitation within 30 days
4.0%
Percentile
90e
Source: FIRST.org, updated on 23 September 2026.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Our own interpretation and context for the source data above.
IACS Radar assessment
Our own interpretation and context for this vulnerability — not an official source.
IACS Radar priority score
Based on CVSS 5.4, EPSS 4.0%, industrial relevance 30/100; raised due to confirmed active exploitation (KEV).
Combines CVSS, EPSS, KEV status, industrial relevance and exposure relevance — a complement to, not a replacement for, the individual scores below and above.
Conditions for exploitation
Operational impact & energy relevance
Limited impact on availability; the risk lies mainly with confidentiality or integrity of process data.
No strong energy-sector-specific signals recognised; general OT/ICS relevance.
Recommended defensive measures
Industrial relevance score
Classification is provisional; manual verification by an OT security analyst is recommended.
Classified by IACS Radar-analysepijplijn (geautomatiseerd) on 24 September 2026.
IEC 62443 mapping
Automatic IACS Radar assessment based on the reported CWE weakness classification; not an official certification statement.