CVE-2025-27915
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What it is
ReportedSynacor Zimbra Collaboration Suite (ZCS) contains a cross-site scripting vulnerability that 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 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.… Source description excerpt; complete tracked detail loads below.
NVD published: Mar 12, 2025 · Source record updated: Aug 8, 2026 · Tracker snapshot: Aug 8, 2026
What is affected
ReportedSynacor — Zimbra Collaboration Suite (ZCS). Product-level identification only; no affected-version conclusion is available from this field.
NVD published: Mar 12, 2025 · Source record updated: Aug 8, 2026 · Tracker snapshot: Aug 8, 2026
Urgency and basis
ReportedAct · 458.3
Tracker decision tier from the evidence detailed below · Source record updated: Aug 8, 2026 · Tracker snapshot: Aug 8, 2026
Exploitation evidence
Reportedkev-listed · CISA KEV · VulnCheck KEV · ENISA exploited-vulnerability catalog
Active since: Oct 7, 2025 · CISA KEV added: Oct 7, 2025 · VulnCheck KEV added: Sep 30, 2025 · ENISA added: Oct 7, 2025 · Source record updated: Aug 8, 2026 · Tracker snapshot: Aug 8, 2026
What to do
ReportedApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Tracked source remediation field · Source record updated: Aug 8, 2026 · Tracker snapshot: Aug 8, 2026
Evidence detail
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