CVE-2025-48700: Synacor Zimbra Collaboration Suite (ZCS) · Cross-site Scripting
Affects Synacor Zimbra Collaboration Suite (ZCS)Source CVE Database V5
Exploited in the wild · KEV due 23 Apr 2026 · 1% EPSS : apply the vendor's fix or mitigations to Synacor Zimbra Collaboration Suite (ZCS) now.
Data as of 26 Oct 2026, 14:05 UTC
- KEV deadline
- US federal agencies must patch by this date; a sensible deadline for everyone else. Other KEV due dates
- EPSS
- 1.7% chance of exploitation in 30 days – higher than 77% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:NExploitation evidence
t = 0 is the CVE’s publication on cve.org
Disclosed: evidence found.
CVE published 23 Jun 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: evidence found.
Listed in CISA KEV 301 days after disclosure
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
Timeline
CVE ID reserved
by MITRE Corporation
, 31 days before disclosure
CVE published
on cve.org
, t = 0
In Threat Radar
record ingested
, the same day as disclosure
Added to CISA KEV (opens in a new tab)
exploitation confirmed
, 301 days after disclosure
KEV remediation due
US federal deadline
, 304 days after disclosure
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Synacor Zimbra Collaboration Suite (ZCS) | Affected
| Fixed in– |
Description
CVE-2025-48700 is a Cross-Site Scripting (XSS) vulnerability affecting Zimbra Collaboration Suite (ZCS) versions 8.8.15, 9.0, 10.0, and 10.1 in the Classic UI. The flaw allows attackers to execute arbitrary JavaScript within a user's session by sending a crafted email containing malicious HTML with an @import directive and other script injection vectors. Exploitation occurs when a user views the malicious email, requiring no further interaction. This can lead to unauthorized access to sensitive information within the affected session. The vulnerability has a CVSS score of 6.