Assessment
Why it matters
CISA lists this vulnerability as known to be exploited; exploitation is confirmed; EPSS is 98.9%; technical severity is CVSS 9.8.
smtp_mailaddr in smtp_session.c in OpenSMTPD 6.6, as used in OpenBSD 6.6 and other products, allows remote attackers to execute arbitrary commands as root via a crafted SMTP session, as demonstrated by shell metacharacters in a MAIL FROM field. This affects the "uncommented" default configuration. The issue exists because of an incorrect return value upon failure of input validation.
Who should care
- Teams operating Ubuntu Linux, Debian Linux, Fedora +1 more
- Vulnerability and exposure management teams
- Security operations teams monitoring exploitation activity
Response plan
What I would do
- Confirm whether Ubuntu Linux, Debian Linux, Fedora +1 more is present in the environment.
- Identify affected versions and establish whether vulnerable services are exposed or reachable.
- Apply updates per vendor instructions.
- Review relevant security telemetry for evidence of attempted or successful exploitation.
- Document the remediation decision and track it to verified completion.
Vendor remediation
Patch and remediation links
Use the vendor source below to confirm the correct fixed version, package or mitigation for your affected product.
Technical details
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CWE
- CWE-755
- Affected versions
- Canonical Ubuntu Linux (Version: 19.10); Debian Debian Linux (Version: 10.0); Fedoraproject Fedora (Version: 32); OpenBSD OpenSMTPD (Version: 6.6)
- Published
- 29 January 2020
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
Signal timeline
- CVE published
- Added to CISA KEV
- Latest EPSS score: 98.9%
- Signal calculated at 85
External references
- Government advisory from www.cisa.gov
- Exploit information from packetstormsecurity.com
- Exploit information from packetstormsecurity.com
- Exploit information from packetstormsecurity.com
- Exploit information from packetstormsecurity.com
- Third-party advisory from packetstormsecurity.com
- Exploit information from seclists.org
- Exploit information from www.openwall.com
- Third-party advisory from lists.fedoraproject.org
- Third-party advisory from seclists.org
- Third-party advisory from usn.ubuntu.com
- Third-party advisory from www.debian.org