CVE-2025-48700

CVE-2025-48700 is a medium-severity vulnerability in Synacor Zimbra Collaboration Suite with a CVSS 3.x base score of 6.1. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2026-04-20). The underlying weakness is classified as CWE-79.

Key facts

Description

An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15 and 9.0 and 10.0 and 10.1. A Cross-Site Scripting (XSS) vulnerability in the Zimbra Classic UI allows attackers to execute arbitrary JavaScript within the user's session, potentially leading to unauthorized access to sensitive information. This issue arises from insufficient sanitization of HTML content, specifically involving crafted tag structures and attribute values that include an @import directive and other script injection vectors. The vulnerability is triggered when a user views a crafted e-mail message in the Classic UI, requiring no additional user interaction.

Frequently asked questions

What is CVE-2025-48700?
An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15 and 9.0 and 10.0 and 10.1. A Cross-Site Scripting (XSS) vulnerability in the Zimbra Classic UI allows attackers to execute arbitrary JavaScript within the user's session, potentially leading to unauthorized access to sensitive information. This issue arises from insufficient sanitization of HTML content, specifically involving crafted tag structures and attribute values that include an @import directive and other script injection vectors. The vulnerability is triggered when a user views a crafted e-mail message in the Classic UI, requiring no additional user interaction.
How severe is CVE-2025-48700?
CVE-2025-48700 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2025-48700 being actively exploited?
Yes. CVE-2025-48700 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2026-04-20, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2025-48700?
CVE-2025-48700 primarily affects Synacor Zimbra Collaboration Suite. In total, 93 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-48700?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2025-48700 have an EU (EUVD) identifier?
Yes. CVE-2025-48700 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-18891. It is also flagged as exploited in the EUVD (since 2026-04-20).
When was CVE-2025-48700 published?
CVE-2025-48700 was published on 2025-06-23 and last updated on 2026-06-17.

References

Affected products (93)

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