CVE-2025-48700
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedAn 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA stored Cross-Site Scripting (XSS) vulnerability exists in Zimbra Collaboration Suite's Classic UI. Attackers inject malicious HTML content (including crafted tag structures with @import directives and other script injection vectors) into emails. When users view these crafted messages in the Classic UI, the insufficient sanitization allows arbitrary JavaScript execution within the user's session, enabling potential session hijacking and sensitive data access.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 10.0.0, < 10.0.12>= 10.1.0, < 10.1.4= 8.8.15= 9.0.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check installed Zimbra versionRun 'zmcontrol -v' or 'zmcontrol status' to retrieve the installed Zimbra Collaboration Suite version numberAffected if The version falls within 10.0.0 through 10.0.11, 10.1.0 through 10.1.3, 8.8.15, or 9.0.0
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Confirm Classic UI is activeLog into the Zimbra web client and verify you are using the Classic UI (look for the legacy interface layout). Alternatively, check the Zimbra configuration file /opt/zimbra/jetty/webapps/zimbra/WEB-INF/web.xml or the user's preferences for the active UI mode.Affected if The Classic UI is enabled or set as the default for users viewing email
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Verify HTML email rendering is enabledCheck if the Zimbra mail store processes and displays HTML emails. This is typically the default behavior. Inspect the Zimbra attribute 'zimbraMailContentHandler' or verify HTML rendering settings in the admin console under MTA or mail receive settings.Affected if HTML email rendering is enabled (this is the default and required for the XSS to trigger)
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Review mail queue for suspicious contentExamine recent incoming emails in the /opt/zimbra/store directory or via 'zmsgrep' for emails containing @import directives or script-related HTML tags. Use 'zmmsgrep' to search for patterns like '@import' within HTML content.Affected if Emails containing unescaped @import directives or script tags are present in user mailboxes
You are affected if your Zimbra version is 8.8.15, 9.0.0, 10.0.0-10.0.11, or 10.1.0-10.1.3 AND users access email through the Classic UI with HTML rendering enabled.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped10.0.1210.1.4
Upgrade to a patched Zimbra version that addresses this vulnerability, or disable the Classic UI and migrate to the modern UI as an interim measure. Implement additional email content sanitization at the mail gateway layer for defense-in-depth.
ZCS 10.0.12+ for 10.0.x branch; ZCS 10.1.4+ for 10.1.x branch; ZCS 10.x LTS for 8.8.15 and 9.0.0
- 1. Identify the currently installed Zimbra Collaboration Suite version using the zmcontrol -v command
- 2. For ZCS 10.0.x versions: Plan upgrade to version 10.0.12 or later which contains the security fix
- 3. For ZCS 10.1.x versions: Plan upgrade to version 10.1.4 or later which contains the security fix
- 4. For ZCS 8.8.15 and 9.0.0: Check Zimbra security advisories on wiki.zimbra.com for specific patch information or consider upgrading to a supported 10.x version
- 5. Before upgrading, ensure complete backup of ZCS configuration, mail stores, and database
- 6. Schedule maintenance window as upgrade may require service downtime
- 7. Perform upgrade following Zimbra official upgrade documentation
- 8. After upgrade, verify the Classic UI properly sanitizes HTML content in email messages
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-48700 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-48700 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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