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Findings

CVE-2025-48700

Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting Vulnerability

Published Jun 23, 2025 · updated Jun 17, 2026 · Synacor Zimbra Collaboration Suite (ZCS)

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.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 23, 2025 · Catalog

    Detected

    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 ta

  2. Apr 20, 2026 · CISA KEV

    Known exploited

    Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

  3. Apr 23, 2026 · CISA KEV

    Remediation due

    Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

  4. Jun 17, 2026 · Catalog

    Updated

    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 ta

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.

CISA due date Apr 23, 2026

Affected

  • cpe synacor/zimbra collaboration suiteversion unspecified
  • cpe synacor/zimbra collaboration suite8.8.15
  • vendor Synacor Zimbra Collaboration Suite (ZCS)version unspecified

Sources

  • CISA KEVCVE-2025-48700

    Synacor Zimbra Collaboration Suite (ZCS) contains a cross-site scripting vulnerability that could allow attackers to execute arbitrary JavaScript within the user's session, potentially leading to unauthorized access to sensitive information.

    cisa.gov
  • CVE.orgCVE-2025-48700

    Official CVE identifier

    cve.org
  • FIRST EPSSCVE-2025-48700

    30-day exploitation probability 1.7%

    first.org
  • NIST NVDCVE-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 se

    nvd.nist.gov

References