SendmailApplication · Eric Allman

CVE-1999-0095

HIGH · 10.0 CVSS v2.0 Published 1988-10-01
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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
The debug command in Sendmail is enabled, allowing attackers to execute commands as root.

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

Sendmail versions prior to patches had the debug command enabled by default, allowing remote attackers to send specially crafted SMTP commands that would be interpreted as shell commands and executed with root privileges on the mail server.

MitigationDisable debug mode in Sendmail configuration files and upgrade to a patched version of Sendmail that has the debug functionality removed or properly secured.

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
SendmailApplication
Affected:= 5.58

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
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:N/AC:L/Au:N/C:C/I:C/A:C

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 Sendmail version
    Run 'sendmail -V' or 'sendmail -d0.1' to display the installed Sendmail version number
    Affected if The version displayed is 5.58 (Eric Allman Sendmail)
  2. Check Sendmail binary location
    Locate the sendmail binary with 'which sendmail' or 'ls -la /usr/sbin/sendmail' and note the binary path
    Affected if The binary is from Sendmail version 5.58
  3. Inspect debug feature in configuration
    Examine the Sendmail configuration file (typically /etc/sendmail.cf or /etc/mail/sendmail.cf) for the 'debug' or 'D' command settings
    Affected if Debug commands are enabled or not commented out in the configuration
  4. Verify debug mode runtime status
    Connect to the SMTP service on port 25 and attempt to issue debug-related SMTP commands (check if the debug command is accepted)
    Affected if The SMTP server accepts and processes debug commands

The system is affected if it runs Sendmail version 5.58 with debug mode enabled in the configuration or at runtime, allowing arbitrary command execution via SMTP.

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

Disable debug mode in Sendmail configuration files and upgrade to a patched version of Sendmail that has the debug functionality removed or properly secured.

Recommended fix Moderate confidence

Migrate from Sendmail 5.58 to a modern mail server (Postfix, Exim, or Sendmail 8.x+)

  1. Identify the current Sendmail version using 'sendmail -V' or 'sendmail -d0.1'
  2. Backup all Sendmail configuration files (/etc/sendmail.cf, /etc/mail/ directory, and aliases)
  3. Stop the Sendmail service using 'service sendmail stop' or '/etc/init.d/sendmail stop'
  4. Upgrade to a modern, supported mail server solution (Sendmail 8.x or alternative such as Postfix, Exim, or Dovecot)
  5. Restore configurations to the new mail server, adapting for current syntax and best practices
  6. Start the new mail service and verify it is running
  7. Test mail functionality to ensure proper operation
Caveat Sendmail 5.58 configuration syntax is incompatible with modern versions; complete configuration migration required; consider migrating to a more modern mail server like Postfix which has better security track record

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

Fix this in Sendmail Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $890
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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-1999-0095 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