CVE-2025-279155.4MediumCWE-79

CVE-2025-27915: Zimbra - Cross-Site Scripting via ICS Files

Synacor · Zimbra Collaboration Suite (ZCS)

Affected: Synacor Zimbra Collaboration Suite (ZCS) · Exploitation: in CISA KEV since 7 Oct 2025

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

ExploitationIn CISA KEV

In CISA KEVCISA KEV catalogue7 Oct 2025
Exploited (reported): not seen
Scanning observed: not seen
Proof of concept public: not seen
Not established: not seen

4.1%probability of exploitation in the next 30 days

90th percentile

050100

Higher than 90% of scored CVEs

5.4MediumCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

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.

On the Atlas

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Open the Atlas

Exploitation: Exploited in the wild. Listed in the CISA Known Exploited Vulnerabilities catalogue.
CISA KEV: Listed since 7 Oct 2025 · catalogue entry
Public check: Zimbra - Cross-Site Scripting via ICS Files · nuclei template in projectdiscovery/nuclei-templates
Weakness: Cross-site Scripting
Vendor: Synacor
Published: March 2025
Band: Exploited in the wild, March 2025

What changed

7 Oct 2025
CISA added it to the KEV catalogue CISA

CoverageNo articles yet

No CyberSIXT article names CVE-2025-27915 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.