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.
do firstApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Can a WAF block it? Yes. The malicious input is delivered via crafted email messages viewed in the web interface. The injected HTML and script content is unusual but may resemble legitimate email content, making it partially filterable by a WAF. A custom WAF rule can filter email messages with crafted HTML content including @import directives and script injection vectors, but attackers can vary the request. No tracked WAF vendor has published a rule for this CVE yet.
What a custom rule would match: email messages with crafted HTML content including @import directives and script injection vectors
Also consider: patch · custom WAF rule · CSP · output encoding
Based on an AI reading of the CVE description, and no vendor rule found yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Is CVE-2025-48700 being exploited?
Yes. CVE-2025-48700 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2025-48700?
CVE-2025-48700 is rated Medium with a CVSS score of 6.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2025-48700?
Yes. A fix has been recorded for CVE-2025-48700. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2025-48700 affect?
CVE-2025-48700 affects synacor:zimbra_collaboration_suite. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
cisa ssvc
- exploitation
- active
- automatable
- no
- technical impact
- partial
Assessed by CISA 20 Apr 2026 (SSVC 2.0.3).
timeline
- 23 Jun 2025Published
- 20 Apr 2026Added to CISA KEV (exploited in the wild) · 300 days (about 10 months) later
- 20 Apr 2026CISA SSVC assessment: exploitation active · same day later
- 21 Apr 2026CVE record last updated · 1 day later
- 23 Apr 2026CISA remediation due date (US federal agencies) · 2 days later
- 2 Nov 2026Analysed by vulneraibility.com · 194 days (about 6 months) later
- Linkwiki.zimbra.com /wiki/Zimbra_Security_Advisories
- Linkwiki.zimbra.com /wiki/Security_Center
- Linkwiki.zimbra.com /wiki/Zimbra_Responsible_Disclosure_Policy
- Linkcisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-48700
sources
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA KEV catalog: exploitation, date added, due date
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.