Zimbra Collaboration SuiteApplication · Synacor

CVE-2018-10949

MEDIUM · 5.3 CVSS v3.0 Published 2018-05-10
Fix available
A fix is available. Upgrade to 8.8.8 or later.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

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
mailboxd in Zimbra Collaboration Suite 8.8 before 8.8.8; 8.7 before 8.7.11.Patch3; and 8.6 allows Account Enumeration by leveraging a Discrepancy between the "HTTP 404 - account is not active" and "HTTP 401 - must authenticate" errors.

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 confidence

The mailboxd component in Zimbra Collaboration Suite returns different HTTP error codes for non-existent accounts versus existing but inactive accounts, allowing attackers to enumerate valid usernames by observing whether they receive a 404 (account not active) or 401 (must authenticate) response.

MitigationUpgrade to Zimbra 8.8.8, 8.7.11.Patch3, or later versions. Alternatively, normalize error responses so both scenarios return identical error codes.

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:>= 8.7.0, <= 8.7.11>= 8.8, < 8.8.8= 8.6.0

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
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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 Zimbra version
    Use the Zimbra administration interface or run 'zmcontrol -v' from the command line to determine the installed Zimbra Collaboration Suite version
    Affected if The installed version falls within 8.6.0, 8.7.0-8.7.11, or 8.8.0-8.8.7
  2. Locate the mailboxd service endpoint
    Identify the exposed HTTP/HTTPS endpoints for the mailboxd component, typically found at /zimbra/ or /mail/ paths on the Zimbra web server
    Affected if The mailboxd HTTP interface is accessible without authentication
  3. Test error response for non-existent account
    Send an HTTP request to the mailboxd endpoint using a clearly non-existent username (e.g., [email protected]) and note the HTTP status code returned
    Affected if A 404 status code is returned for the non-existent account
  4. Test error response for existing but inactive account
    Send an HTTP request using a username that exists in the directory but has an inactive account status, and note the HTTP status code returned
    Affected if A 401 status code (or different code from step 3) is returned for the inactive account

A user is affected if their Zimbra version is 8.6.0, 8.7.0-8.7.11, or 8.8.0-8.8.7 AND the mailboxd endpoint returns different HTTP error codes (404 vs 401) for non-existent versus existing but inactive accounts, enabling username enumeration.

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.

From vendor data
Upgrade available Upgrade to 8.8.8 or later
Fixed in 8.8.8
Interim mitigation

Upgrade to Zimbra 8.8.8, 8.7.11.Patch3, or later versions. Alternatively, normalize error responses so both scenarios return identical error codes.

Fix this in Zimbra Collaboration Suite Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,328.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2018-10949 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-10949 in production — separate from our analysis above.

No notes yet

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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