dbcve.org
SmartermailApplication · Smartertools

CVE-2021-43977

MEDIUM · 6.1 CVSS v3.1 Published 2021-11-17
Fix available
A fix is available. Upgrade to 100.0.7803 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
SmarterTools SmarterMail 16.x through 100.x before 100.0.7803 allows XSS.

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

SmarterTools SmarterMail versions 16.x through 100.x before 100.0.7803 contains a Cross-Site Scripting (XSS) vulnerability that allows remote attackers to inject malicious scripts into web pages viewed by other users. This is likely a stored XSS vulnerability in the webmail interface, enabling session hijacking or credential theft.

MitigationUpgrade SmarterMail to version 100.0.7803 or later. Until patched, implement Content Security Policy (CSP) headers and sanitize user-generated content in the mail interface.

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
SmartermailApplication
Affected:>= 16.0.6345, < 100.0.7803

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. Locate the SmarterMail version number
    Access the SmarterMail administration interface and navigate to the About or System Information page, typically found under Help or System menu. The version is also sometimes displayed in the footer of the webmail login page.
    Affected if The displayed version falls within 16.0.6345 through 100.0.7802 (versions below 100.0.7803, starting from 16.0.6345)
  2. Confirm version via help/about endpoint
    If available, access the /help/about or /about endpoint on the SmarterMail server (e.g., https://mail.yourdomain.com/help/about) to retrieve the exact build version.
    Affected if The version returned is within the affected range (>= 16.0.6345 and < 100.0.7803)
  3. Verify webmail interface is enabled
    Check the SmarterMail service status and confirm the webmail interface is accessible by attempting to load the login page (typically at /webmail or the root URL of the mail server).
    Affected if The webmail interface is active and accessible to users, which is required for the stored XSS to be exploitable
  4. Review recent webmail activity logs
    Examine the SmarterMail logs (located in the Logs folder of the installation directory) for any suspicious user submissions or unexpected script tags in message content, subject lines, or contact fields.
    Affected if Unusual patterns of script tags or HTML injection attempts appear in mail-related logs

You are affected if the installed SmarterMail version is 16.0.6345 or higher but below 100.0.7803 and the webmail interface is enabled.

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 100.0.7803 or later
Fixed in 100.0.7803
Interim mitigation

Upgrade SmarterMail to version 100.0.7803 or later. Until patched, implement Content Security Policy (CSP) headers and sanitize user-generated content in the mail interface.

Recommended fix High confidence

100.0.7803 or later

  1. Back up the current Smartermail installation, configuration, and all mail data before proceeding with any upgrade.
  2. Download Smartermail version 100.0.7803 or later from the official SmarterTools website (www.smartertools.com).
  3. Stop the Smartermail service to ensure a clean upgrade process.
  4. Follow the standard Smartermail upgrade installation procedure - run the installer and follow the on-screen prompts.
  5. After installation completes, restart the Smartermail service.
  6. Verify the upgrade was successful by checking the version number in the Smartermail administration interface.
  7. Confirm the XSS vulnerability is resolved by validating that user input is properly sanitized in the affected components.

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

Fix this in Smartermail Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,664.

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-2021-43977 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