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VulnerabilityPublished Updated

CVE-2025-48700: Synacor Zimbra Collaboration Suite (ZCS) · Cross-site Scripting

Affects Synacor Zimbra Collaboration Suite (ZCS)Source CVE Database V5

0

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

CVSS 3.1 base score
6.1Medium
How severe the flaw is on the 0–10 CVSS scale.
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:N

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

  1. Disclosed: evidence found.

    CVE published 23 Jun 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: evidence found.

    Listed in CISA KEV 301 days after disclosure

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

Timeline

  1. CVE ID reserved

    by MITRE Corporation

    , 31 days before disclosure

  2. CVE published

    on cve.org

    , t = 0

  3. In Threat Radar

    record ingested

    , the same day as disclosure

  4. , 301 days after disclosure

  5. 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

ProductAffectedFixed in
Synacor Zimbra Collaboration Suite (ZCS)Affected
  • 8.8.15 – 10.1
4 affected builds
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.

References

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