CVE-2020-7247: OpenSMTPD Remote Code Execution Vulnerability

Distribution release	Source package	Vendor state	Fixed version	Evidence
Alpine v3.23v3.23 · community	`opensmtpd`	Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.	`6.6.2p1-r0`	Alpine Security Database ↗Source updated 22 Oct 2026
Alpine v3.22v3.22 · community	`opensmtpd`	Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.	`6.6.2p1-r0`	Alpine Security Database ↗Source updated 22 Oct 2026
Alpine v3.21v3.21 · community	`opensmtpd`	Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.	`6.6.2p1-r0`	Alpine Security Database ↗Source updated 22 Oct 2026
Debian trixietrixie · source	`opensmtpd`	Vendor fix publishedDebian records a fixed source-package version for this release.	`6.6.2p1-1`	Debian Security Tracker ↗Source updated 24 Oct 2026
Debian bookwormbookworm · source	`opensmtpd`	Vendor fix publishedDebian records a fixed source-package version for this release.	`6.6.2p1-1`	Debian Security Tracker ↗Source updated 24 Oct 2026
Debian forkyforky · source	`opensmtpd`	Vendor fix publishedDebian records a fixed source-package version for this release.	`6.6.2p1-1`	Debian Security Tracker ↗Source updated 24 Oct 2026
Debian sidsid · source	`opensmtpd`	Vendor fix publishedDebian records a fixed source-package version for this release.	`6.6.2p1-1`	Debian Security Tracker ↗Source updated 24 Oct 2026

Recommended actionPatch now

CISA confirms exploitation in the wild and lists 2022-04-15 as the remediation due date.

Patch available

What, why and how

smtp_mailaddr in smtp_session.c in OpenSMTPD, as used in OpenBSD and other products, allows remote attackers to execute arbitrary commands as root via a crafted SMTP session.

What

smtp_mailaddr in smtp_session.c in OpenSMTPD, as used in OpenBSD and other products, allows remote attackers to execute arbitrary commands as root via a crafted SMTP session.

Why

The product does not handle or incorrectly handles an exceptional condition.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may execute code or commands in the affected security context.

What

smtp_mailaddr in smtp_session.c in OpenSMTPD, as used in OpenBSD and other products, allows remote attackers to execute arbitrary commands as root via a crafted SMTP session.

Why

The product does not handle or incorrectly handles an exceptional condition.

How

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2022-03-25.

Public PoC / exploit material

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path: a network path → Improper Handling of Exceptional Conditions → execute code or commands in the affected security context
Attack surface: Network
Privileges required: None: unauthenticated exploitation is possible
User interaction: None
Attack complexity: Low: no specialised conditions are recorded
Security boundary: Unchanged: impact remains within the vulnerable component's security authority
Weakness ? CWE means Common Weakness Enumeration: a standard category for the underlying weakness.: CWE-755 ↗
CWE-755: Improper Handling of Exceptional Conditions. The product does not handle or incorrectly handles an exceptional condition.
CVSS vector ? CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land: After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.

NetworkUnauthenticatedRemote code executionCWE-755CISA KEVPublic exploit reference

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2020-28374Known-exploited evidence recorded

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.

Official EUVD record ↗

JVN iPedia · Japanese · JVNDB-2020-001354OpenSMTPD に権限昇格と任意コード実行の脆弱性

OpenSMTPD には、権限昇格や任意のコード実行が可能な脆弱性が存在します。 OpenSMTPD は、 OpenBSD Project が提供するオープンソースの SMTP サーバです。OpenSMTPD は smtp_mailaddr() 関数により送信者と受信者のメールアドレスを検証します。メールアドレスのローカルパートが無効な文字列で、かつドメイン名の文字列が空白となるような、本来ならば無効なアドレスであった場合、smtp_mailaddr() 関数はこれにデフォルトのドメイン名を付け加えますが、エラーとして扱いません。このため、無効なアドレスであっても関数による検証が行われない状況が生じます。

Official advisory ↗

KISA KrCERT/CC · Korean · KNVD-5251주요 보안 취약점 업데이트를 재확인 하세요!!

#### 주요 보안 취약점 업데이트를 재확인 하세요!! 2021.01.05 ##### □ 개요 o `20년 보안공지 된 취약점 중 업데이트 적용에 대한 재확인이 필요한 주요 취약점 리스트 ※ 미국 NSA 발표, 랜섬웨어 유포에 악용된 취약점 등 이슈화 된 취약점 선정 ##### □ 주요 내용 No 구분 CVE번호 제조사 제품명 취약점 종류 패치정보 및 보안공지 1 네트워크 CVE-2019-15978 외 10개 Cisco Data Center Network Manager 명령어 삽입 취약점 등 [1] 2 네트워크 CVE-2019-19781 Citrix ADC, Gateway,SDWAN-WANOP 임의코드 실행 취약점 [2] 3 네트워크 CVE-2020-11896 Cisco ASR 500,5500 원격코드 실행 취약점 [3] 4 운영체제 CVE-2020-7247 - OpenSMTPD 원격코드 실행 취약점 [4] 5 운영체제 CVE-2020-0674 MS 인터넷 익스플로러 원격코드 실행 취약점 [5] 6 운영체제 CVE-2020-0688 MS 윈도우 Exchange 서버 원격코드 실행 취약점 [6] 7 운영체제 CVE-2020-0796 MS 윈도우 SMBv3 원격코드 실행 취약점 [7] 8 운영체제 CVE-2019-14287 유닉스/리눅스 - sudo 명령어 취약점 [8] 9 운영체제 CVE-2020-1472 MS 윈도우 서버 Netlogon 권한상승 취약점 [9] 10 가상화 CVE-2020-3943 외 2개 VMware vRealize Operations 임의코드 실행 취약점 등 [10] 11 가상화 CVE-2020-3952 VMware vCenter Server 정보유노출 취약점 [11] 12 웹서버 CVE-2020-1938 Apache Tomcat 원격코드 실행 취약점 [12] 13 보안솔루션 CVE-2020-7845 지란지교시큐리티 스팸스나이퍼 버퍼오버플로우 취약점 [13] 14 보안솔루션 CVE-2020-25043 외 11개 Kaspersky 등 7개사 백신프로그램 임의파일 삭제 취약점 등 [14] 15 원격협업 CVE-2020-6109 외 1개 Zoom Zoom 임의파일 쓰기 취약점 [15]

Official advisory ↗

KISA KrCERT/CC · Korean · KNVD-5089OpenSMTPD 보안 업데이트 권고

smtp_mailaddr 함수에서 사용자의 입력값에 대한 검증이 미흡하여 발생하는 원격코드실행 취약점(CVE-2020-7247) [1][2]

Official advisory ↗

Patch and workaround

Operational remediation based on structured source evidence.

Status ? Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.: Patch available
Affected: n/a
Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action: Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround: No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.

Evidence and provenance

Published 29 Jan 2020 · Last source change 21 Oct 2025, 23:35 UTC · CWE-755 · Improper Handling of Exceptional Conditions

CVE recordCVE.org · 5.1

CVSS sourceNIST NVD

EPSS source

The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.

FIRST · tracked since 2026-08-14

European sourceENISA EUVD · EUVD-2020-28374

Product sourceCISA KEV

Remediation sourceCVE/CNA references

CWE sourceCISA ADP

NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗

21 Oct 2025, 23:35 UTC
Affected versionsThe structured affected or fixed version information changed.
Before
n/a: n/a · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
After
n/a · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
CISA KEV ↗
21 Oct 2025, 23:35 UTC
Affected versionsThe structured affected or fixed version information changed.
Before
n/a · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
After
n/a: n/a · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
CNA ↗

2020-01-29CVE published

2022-03-25Added to CISA KEV

2025-10-21Fixed release or patch reference recorded

ENISA EUVD · EUVD-2020-28374↗CISA KEV record↗CVE authority or vendor reference↗Patch or update reference↗Public exploit reference↗Public exploit reference↗Official CVE record (CNA and ADP data)↗NVD record↗

Technical terms and abbreviations used in this report

CVE: Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS: Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS: Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE: Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA: CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP: Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD: National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT: A computer security incident response team that publishes warnings or coordinates incident response.
PoC: Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF: Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL: Living off the land: abuse of legitimate tools or system functions during an attack.

OpenSMTPD Remote Code Execution Vulnerability

Published severity in operational context

Evidence used

Compensating controls

Verification

Release-specific package status

National CERT insights
?
CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

ENISA European Vulnerability Database

EUVD-2020-28374

What, why and how

Exploit reality and attack path

Official authority intelligence

Patch and workaround

Evidence and provenance

What changed after publication