Mailcow\Application · Mailcow

CVE-2023-49077

MEDIUM · 6.1 CVSS v3.1 Published 2023-11-30
Fix available
A fix is available. Upgrade to 2023-11 or later.
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
Mailcow: dockerized is an open source groupware/email suite based on docker. A Cross-Site Scripting (XSS) vulnerability has been identified within the Quarantine UI of the system. This vulnerability poses a significant threat to administrators who utilize the Quarantine feature. An attacker can send a carefully crafted email containing malicious JavaScript code. This issue has been patched in version 2023-11.

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

A stored Cross-Site Scripting (XSS) vulnerability exists in the Mailcow Quarantine UI. Attackers can inject malicious JavaScript code into email content viewed through the quarantine feature, which executes when administrators access the quarantine interface.

MitigationUpgrade Mailcow to version 2023-11 or later. Prior to upgrade, review current quarantine settings and ensure backups are available.

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
Mailcow\Application
Affected:< 2023-11

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. Check Mailcow version
    Run: docker ps --format '{{.Names}}' | grep mailcow && docker exec -it mailcow mailcow-ui bash -c 'cat /etc/os-release' or check the Mailcow UI footer for version number
    Affected if Version shown is earlier than 2023-11 (e.g., 2023-10, 2023-09, etc.)
  2. Verify quarantine feature is enabled
    Log into Mailcow UI as administrator, navigate to Quarantine settings (usually under Quarantine > Settings) or check the mailcow.conf file for quarantine-related configuration flags
    Affected if Quarantine is enabled and storing email content
  3. Check quarantine database for suspicious content
    Connect to the mailcow MySQL container (docker exec -it mailcow-mysql mysql -u mailcow -p mailcow) and query the quarantine table for unusual patterns: SELECT * FROM quarantine WHERE subject LIKE '%<script%' OR body LIKE '%<script%' OR FROM LIKE '%script%';
    Affected if Any records contain HTML script tags or encoded JavaScript in subject, body, or sender fields
  4. Review administrator access logs
    Check Mailcow logs for administrator logins to quarantine: docker logs mailcow-ui 2>&1 | grep -i quarantine or review reverse proxy/access logs for /webmail/src/../quarantine endpoints
    Affected if Unusual IP addresses or times accessing the quarantine interface are present

A user is affected if their Mailcow installation is version 2023-10 or earlier AND the quarantine feature is enabled, as the XSS only triggers when administrators view quarantined email content.

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
Upgrade available Upgrade to 2023-11 or later
Fixed in 2023-11
Interim mitigation

Upgrade Mailcow to version 2023-11 or later. Prior to upgrade, review current quarantine settings and ensure backups are available.

Recommended fix High confidence

Mailcow version 2023-11 or later

  1. Ensure you have a backup of your Mailcow data and configuration
  2. Access your Mailcow server via command line
  3. Navigate to your Mailcow directory (where docker-compose.yml is located)
  4. Run the Mailcow update script typically found in the repository (e.g., ./update.sh)
  5. Alternatively, pull the latest Mailcow docker images: docker-compose pull
  6. Restart Mailcow containers: docker-compose up -d
  7. Verify the upgrade was successful by checking the Mailcow UI version information
  8. Log in to the Quarantine UI to confirm the vulnerability is patched
Caveat Standard Mailcow upgrades are generally safe but always backup data first; minor configuration adjustments may be needed if using custom templates

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

Fix this in Mailcow\ Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,390
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Scan for this in your stack

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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-2023-49077 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