dbcve.org
Zimbra Collaboration SuiteApplication · Synacor

CVE-2020-18984

MEDIUM · 6.1 CVSS v3.1 Published 2021-12-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

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 · unedited
A reflected cross-site scripting (XSS) vulnerability in the zimbraAdmin/public/secureRequest.jsp component of Zimbra Collaboration 8.8.12 allows unauthenticated attackers to execute arbitrary web scripts or HTML via a host header injection.

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 confidence

A reflected cross-site scripting (XSS) vulnerability in zimbraAdmin/public/secureRequest.jsp of Zimbra Collaboration 8.8.12 allows unauthenticated attackers to inject arbitrary HTML or JavaScript through manipulation of the HTTP Host header.

MitigationUpdate Zimbra to a patched version or apply vendor-provided security patches; configure the web server to validate and whitelist expected Host header values to prevent host header injection.

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
Zimbra Collaboration SuiteApplication
Affected:= 8.8.12

CVSS 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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Zimbra version
    Run 'zmcontrol -v' as the zimbra user or check /opt/zimbra/.git describe --tags to determine the exact version installed
    Affected if The installed version is exactly 8.8.12
  2. Confirm zimbraAdmin interface is accessible
    Attempt to access https://your-server:7071/zimbraAdmin/ or check if port 7071 is open and responding
    Affected if The zimbraAdmin interface is publicly or internally accessible on the network
  3. Verify the vulnerable secureRequest.jsp exists
    Check for the file at /opt/zimbra/jetty/webapps/zimbraAdmin/public/secureRequest.jsp on the Zimbra server
    Affected if The secureRequest.jsp file exists in the expected location and is served by the admin web application
  4. Inspect Host header configuration
    Review the Zimbra proxy configuration or web server (Jetty) configuration files for Host header validation settings
    Affected if The server accepts arbitrary Host header values without validation or whitelisting

A system is affected if it runs Zimbra version 8.8.12 and has the zimbraAdmin interface accessible with the vulnerable secureRequest.jsp endpoint present.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update Zimbra to a patched version or apply vendor-provided security patches; configure the web server to validate and whitelist expected Host header values to prevent host header injection.

Recommended fix Moderate confidence

Zimbra Collaboration 8.8.15 (latest 8.8.x stable) or Zimbra 9.0 (modern release)

  1. Identify the current Zimbra installation version by checking /opt/zimbra/.platform_version or running 'zmcontrol -v'
  2. Download the latest Zimbra Collaboration 8.8.15 patch or migrate to Zimbra 9.0 from https://www.zimbra.com/download/
  3. Before upgrading, backup the Zimbra directory with 'rsync -av /opt/zimbra/ /opt/zimbra.backup/' and database with 'zmcontrol stop' followed by mysqldump of all zimbra databases
  4. Review /opt/zimbra/conf/localconfig.xml for custom configurations that may need restoration post-upgrade
  5. Execute the upgrade installer as the zimbra user: './install.sh' from the downloaded package
  6. After upgrade completes, verify all services start correctly with 'zmcontrol start' and 'zmcontrol status'
  7. Validate the fix by testing that the zimbraAdmin/public/secureRequest.jsp endpoint no longer reflects arbitrary host header values in the response
Caveat Major version upgrade to 9.0 may require migration planning; review Zimbra migration guide for mailbox and configuration transfer steps

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Zimbra Collaboration Suite Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,224.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2020-18984 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-18984 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data