CVE-2025-27915
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network with a low-privilege account, but needs a user to act. Limited direct impact.
- In the wild
- CISA lists this as exploited in real attacks. Treat as urgent.
- Fix
- No patch or advisory is linked yet. Look at mitigations or restrict exposure.
Timeline
- ReservedThe CVE id was reserved by its CNA
- PublishedDisclosed publicly on CVE.org and NVD
- 2025-10-07 Exploited in the wildAdded to CISA's Known Exploited Vulnerabilities list
- 2025-10-28 Remediation deadlineCISA's due date for federal agencies to fix it
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: yes, CISA lists it. This puts it above everything that is not.
- Exploit odds: 4.1% in the next 30 days (EPSS).
- Severity: 5.4 MEDIUM (CVSS).
- Fix: none linked yet, which raises it.
Details
- Published
- Last modified
- Added to CISA KEV
- 2025-10-07
- Exploit probability
- 4.1% · EPSS, next 30 days
- Weakness
- CWE-79 · Cross-site scripting
- Record status
- Analyzed
Affected
- Synacor Zimbra Collaboration Suite < 10.0.13
- Synacor Zimbra Collaboration Suite < 10.1.5
- Synacor Zimbra Collaboration Suite 9.0.0
Attack profile CVSS 3.1 · 5.4
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2025-27915.md and follow it. Check whether this project is affected by CVE-2025-27915. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
References
- https://wiki.zimbra.com/wiki/Security_Center
- https://wiki.zimbra.com/wiki/Zimbra_Releases/10.0.13#Security_Fixes
- https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.5#Security_Fixes
- https://wiki.zimbra.com/wiki/Zimbra_Releases/9.0.0/P44#Security_Fixes
- https://strikeready.com/blog/0day-ics-attack-in-the-wild/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-27915