CVE-2020-11737
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 · uneditedA cross-site scripting (XSS) vulnerability in Web Client in Zimbra 9.0 allows a remote attacker to craft links in an E-Mail message or calendar invite to execute arbitrary JavaScript. The attack requires an A element containing an href attribute with a "www" substring (including the quotes) followed immediately by a DOM event listener such as onmouseover. This is fixed in 9.0.0 Patch 2.
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 · high confidenceA reflected XSS vulnerability in Zimbra 9.0 Web Client allows attackers to inject arbitrary JavaScript via specially crafted links in emails or calendar invites. The attack vector requires an <a> element with an href attribute containing the literal string 'www' (including quotes) immediately followed by a DOM event handler like onmouseover, suggesting a parser bypass or sanitization edge case.
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= 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.
-
Check Zimbra Collaboration Suite versionRun 'zmcontrol -v' or check /opt/zimbra/.version to determine the installed Zimbra versionAffected if Version is exactly 9.0.0 with no patches applied (Patch 2 or later is required to remediate)
-
Confirm Zimbra Web Client is enabledAccess the Zimbra web mail interface via browser at the mail server URL to verify the Web Client is availableAffected if Web Client is accessible and the server version is 9.0.0 unpatched
-
Determine if email gateway filtering is activeReview mail gateway or MTA configuration to check if content filtering is applied to inbound email messagesAffected if No email content filtering is present and version is 9.0.0 unpatched
Environment is affected if running Zimbra version exactly 9.0.0 with the Web Client enabled and no email content filtering at the gateway layer to block specially crafted email content.
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.
From vendor dataApply Zimbra 9.0.0 Patch 2 or later to remediate this vulnerability. Organizations should also consider email content filtering at the gateway layer as a defense-in-depth measure.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-11737 — 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-2020-11737 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
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.
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.
- 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