CVE detail
CVE-2025-27915: Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting Vulnerability
Source: CISA Known Exploited Vulnerabilities catalog · back to feed
Vendor / product
Synacor · Zimbra Collaboration Suite (ZCS)
- Date added (KEV)
- Oct 07, 2025
- CISA due date
- Oct 28, 2025
- Ransomware campaign use
- Unknown
Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Vendor fix: Vendor advisory
Scorifya interpretation
AI-generatedA short, structured read of the record above — generated when this page first loads, then cached for a week.
Plain English
Technical detail
From CISA
Synacor 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. As a result, an attacker can perform unauthorized actions on the victim's account, including e-mail redirection and data exfiltration.
https://wiki.zimbra.com/wiki/Security_Center ; https://nvd.nist.gov/vuln/detail/CVE-2025-27915
References
- https://wiki.zimbra.com/wiki/Security_CenterRelease Notes
- https://wiki.zimbra.com/wiki/Zimbra_Releases/10.0.13#Security_FixesRelease Notes
- https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.5#Security_FixesRelease Notes
- https://wiki.zimbra.com/wiki/Zimbra_Releases/9.0.0/P44#Security_FixesRelease Notes
- https://strikeready.com/blog/0day-ics-attack-in-the-wild/ExploitThird Party Advisory
Other recent CVEs from Synacor
- CVE-2025-48700Zimbra Collaboration Suite (ZCS) — Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting Vulnerability
- CVE-2025-66376Zimbra Collaboration Suite (ZCS) — Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting Vulnerability
- CVE-2020-7796Zimbra Collaboration Suite — Synacor Zimbra Collaboration Suite (ZCS) Server-Side Request Forgery Vulnerability
- CVE-2025-68645Zimbra Collaboration Suite (ZCS) — Synacor Zimbra Collaboration Suite (ZCS) PHP Remote File Inclusion Vulnerability
- CVE-2019-9621Zimbra Collaboration Suite (ZCS) — Synacor Zimbra Collaboration Suite (ZCS) Server-Side Request Forgery (SSRF) Vulnerability
Check your domain's public posture
Scorifya doesn't test for specific CVEs, but if patching Synacor changed your headers or TLS, a fresh hardening scan helps confirm nothing regressed externally.