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CVE-2020-7247

OpenBSD — OpenSMTPD Remote Code Execution Vulnerability

OpenBSD · CWE-78 — Operating system command injection | CWE-755 · in CISA KEV since 2022-03-25

ExigentKEV since 2022 · listed over a yearCISA KEVActively Exploited
87

EVRS 87 of 100 Immediate

Out-of-Band / Urgent Remediation

Rank 261 of 2,960 tracked

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Why it scores 87

Evidence available: 6 of 7 signals

Listed in the CISA KEV catalog, and an EPSS probability of 0.990.

  • CISA KEVApplied
  • RansomwareDid not apply
  • Vendor exploitationDid not apply
  • EPSSApplied
  • Microsoft Exploitability IndexNot applicable
  • Pre-patch disclosureNo data
  • KEV recencyDid not apply
  • CVSSApplied

The band answers “how soon”, not “how bad”. No data for: Pre-patch disclosure. Why some signals show no data

Fix

Patch or fixed version identified

CISA required action

Fixed in

opensmtpd -> 6.0.3p1-1ubuntu0.1 | opensmtpd -> 5.4.1p1-1ubuntu0.1~esm1 | opensmtpd -> 5.7.3p2-1ubuntu0.1~esm1 | opensmtpd -> 6.6.2p1-1

Affected versions

  • opensmtpd6.6
  • debian linux9.010.0
  • fedora32
  • ubuntu linux18.0419.10

Remediation

Apply updates per vendor instructions.

Fixed versions from NVD.

Evidence

Each value with its source
MeasureValueSource
CVSS base scoreHow severe the flaw is in itself. It does not say how likely an attack is. 9.8 NVD
FIRST EPSSFIRST's estimate of the chance this is exploited in the next 30 days, and how that ranks against all CVEs. 0.990 (99.93rd pctl) FIRST EPSS
Actively exploitedWhether a source of record has confirmed attacks using it in the wild. Confirmed CISA KEV
Ransomware campaign useWhether CISA has seen ransomware operators use it. Unknown or none CISA KEV
CISA remediation deadlineThe date US federal agencies must have fixed or mitigated it. 2022-04-15 · KEV since 2022 · listed over a year CISA KEV
Public exploit moduleA module existing is not the same as active exploitation. Public module exists Metasploit
EUVD cross-referenceENISA's record: CVSS 9.8 (v3.1), assigned by mitre. Listed ENISA EUVD

Description

NVD

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.

What CISA says to do

Public module

Metasploit lists a public excellent-rank module for this CVE: OpenSMTPD MAIL FROM Remote Code Execution (unix/smtp/opensmtpd_mail_from_rce). A module existing is not the same as active exploitation; see metasploit.com.