Your RSA-2048 keys break in 2030. Find every one of them before attackers do.
🛡️
CISA KEV · ACTIVELY EXPLOITED
CRITICAL severity

CVE-2020-7247

CRITICALFix: openbsd/src@9dcfda0

CVE-2020-7247 is a critical-severity (CVSS 9.8) OS Command Injection vulnerability. It is in CISA's Known Exploited Vulnerabilities catalog (added 2022-03-25) — treat it as actively exploited and patch now. O3 Security confirms whether CVE-2020-7247 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Published
Jan 29, 2020
Updated
Apr 11, 2026
Affected
0 pkgs
Patched
None yet
Exploits
21 known
Exploitation data as of Aug 27, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

  • Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2022-03-25. Federal agencies were required to remediate by 2022-04-15.
  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2020-7247.

EPSS Exploitation Probability

via FIRST.org ↗
99.0%probability of exploitation in next 30 days
Very High Risk+4.90%
Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk
92.6%95.1%97.5%100.0%94.1%94.1%94.1%99.0%Feb 26Apr 26Aug 26

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

CVE-2020-7247 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE sits: patch-first territory.

Where this sits among everything scored

Of 368,770 CVEs with a current EPSS score, this one falls in the ≥ 90% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Description

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.

Exploits & PoCs
21

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

EDB-47984remotelinux✓ Verified

OpenSMTPD 6.6.1 - Remote Code Execution

by 1F98D · Jan 30, 2020

EDB-48038remotelinux✓ Verified

OpenSMTPD - MAIL FROM Remote Code Execution (Metasploit)

by Metasploit · Feb 10, 2020

EDB-48051remoteopenbsd✓ Verified

OpenSMTPD 6.4.0 < 6.6.1 - Local Privilege Escalation + Remote Code Execution

by Marco Ivaldi · Feb 11, 2020

Detection & mitigation playbook

Vulnerability
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Remediation status

    No patched version of the affected component has shipped for CVE-2020-7247 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

  3. Mitigate without a patch

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether CVE-2020-7247 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2020-7247. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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.
O3 Security · Impact-Aware SCA

Is CVE-2020-7247 in your dependencies?

O3 detects CVE-2020-7247 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

CVE-2020-7247: critical severity vulnerability… | O3 Security