dbcve.org
CollaborationApplication · Zimbra

CVE-2023-24030

MEDIUM · 6.1 CVSS v3.1 Published 2023-06-15
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
An open redirect vulnerability exists in the /preauth Servlet in Zimbra Collaboration Suite through 9.0 and 8.8.15. To exploit the vulnerability, an attacker would need to have obtained a valid zimbra auth token or a valid preauth token. Once the token is obtained, an attacker could redirect a user to any URL if url sanitisation is bypassed in incoming requests. NOTE: this is similar, but not identical, to CVE-2021-34807.

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

An open redirect vulnerability exists in the /preauth Servlet of Zimbra Collaboration Suite (versions 8.8.15 through 9.0). An attacker who has obtained a valid zimbra auth token or preauth token can bypass URL sanitization in incoming requests to redirect authenticated users to arbitrary external URLs.

MitigationApply vendor patches when available. In the interim, implement strict URL allow-listing for redirect destinations and enforce short token expiration with automatic rotation to limit token theft exposure.

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
CollaborationApplication
Affected:= 8.8.15= 9.0.0

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
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 Zimbra installation version
    Run 'zmcontrol -v' or check the Zimbra package version installed on the server (e.g., 'rpm -qa | grep zimbra' or 'apt list --installed | grep zimbra')
    Affected if The installed version is 8.8.15 or 9.0.0 (exact match per the affected range)
  2. Confirm Zimbra service is running
    Run 'zmcontrol status' to verify that the Zimbra mail server services are active
    Affected if Services are running, meaning the vulnerable /preauth Servlet is exposed
  3. Check for exposed /preauth endpoint
    Verify the Zimbra web server is accepting connections on ports 80/443 or 8080/8443 and test for the /preauth path availability
    Affected if The /preauth servlet is accessible without additional authentication barriers
  4. Review redirect validation configuration
    Inspect Zimbra configuration files (typically in /opt/zimbra/conf/ or via 'zmprov gcf') for settings controlling URL redirect allow-listing or validation
    Affected if No strict URL allow-listing is configured for redirect destinations, or the configuration allows arbitrary external URLs

A Zimbra server is affected if it runs version 8.8.15 or 9.0.0, has the /preauth servlet accessible, and lacks strict URL allow-listing for redirect destinations.

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

Apply vendor patches when available. In the interim, implement strict URL allow-listing for redirect destinations and enforce short token expiration with automatic rotation to limit token theft exposure.

Recommended fix Moderate confidence

8.8.15 Patch 18+ or 9.0.0 Patch 15+ (or latest stable 9.x release)

  1. Check current Zimbra version using: zmcontrol -v
  2. For 8.8.15: Upgrade to 8.8.15 Patch 18 or later
  3. For 9.0.0: Upgrade to 9.0.0 Patch 15 or later
  4. Alternatively, upgrade to Zimbra Collaboration 9.0.1 or latest stable release
  5. After upgrade, verify the /preauth endpoint no longer allows arbitrary URL redirection
  6. Review Zimbra Wiki security notices for patch-specific documentation
Caveat Major version upgrades may require migration planning; test in staging first

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

Fix this in Collaboration Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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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-2023-24030 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