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CVE-2019-16928 — Exim 4.92 through 4.92.2 allows remote code execution, a different vulnerability than…

Key facts

CVE-2019-16928 is a Critical (9.8) vulnerability: Exim 4.92 through 4.92.2 allows remote code execution, a different vulnerability than…. This entry ships a detection-only PoC and a Docker test lab. It is on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2022-03-03), confirming active exploitation in the wild.

Actively exploited — on the CISA KEV catalog

CVE-2019-16928 is listed on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2022-03-03), confirming exploitation in the wild. Federal remediation deadline: 2022-03-17. Prioritise patching and deploy the detection and prevention rules below.
CVE CVE-2019-16928
Severity Critical (9.8)
CISA KEV Actively exploited (added 2022-03-03)
Detection / prevention —
PoC poc.py
Source 2019/CVE-2019-16928/

Details

English | 한국어

Description

Exim 4.92 through 4.92.2 allows remote code execution, a different vulnerability than CVE-2019-15846. There is a heap-based buffer overflow in string_vformat in string.c involving a long EHLO command.

Vulnerability Details

Property Value
CVE ID CVE-2019-16928
Type RCE
CVSS Score 9.8

Proof of Concept

Download

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2019/CVE-2019-16928/poc.py

Usage

# Run PoC against target
python3 poc.py --target <TARGET_URL>

# With authentication
python3 poc.py --target <TARGET_URL> --username <USER> --password <PASS>

⚠️ Warning: This PoC is for authorized security testing only. It uses detection-only techniques and does not exploit or damage target systems.

Test Lab

This repository includes a Docker-based test environment with both vulnerable and patched applications.

Quick Start

# Clone and navigate to CVE directory
cd CVE-2019-16928

# Start both applications
docker-compose up -d

# Run tests
./run-tests.sh    # Linux/Mac
./run-tests.ps1   # Windows PowerShell

Application Endpoints

Application URL Status
Vulnerable App http://localhost:8080 Shows vulnerability
Patched App http://localhost:8081 Demonstrates fix

Directory Structure

├── README.md           # English documentation
├── README_KO.md        # Korean documentation
├── poc.py              # PoC detection script
├── docker-compose.yml  # Container orchestration
├── run-tests.sh        # Linux/Mac test runner
├── run-tests.ps1       # Windows test runner
├── vulnerable-app/     # Vulnerable version
│   ├── app.py
│   ├── Dockerfile
│   └── requirements.txt
└── patched-app/        # Fixed version
    ├── app.py
    ├── Dockerfile
    └── requirements.txt

References

  • http://www.openwall.com/lists/oss-security/2019/09/28/1
  • http://www.openwall.com/lists/oss-security/2019/09/28/2
  • http://www.openwall.com/lists/oss-security/2019/09/28/3
  • http://www.openwall.com/lists/oss-security/2019/09/28/4
  • https://bugs.exim.org/show_bug.cgi?id=2449
  • https://git.exim.org/exim.git/commit/478effbfd9c3cc5a627fc671d4bf94d13670d65f
  • https://lists.exim.org/lurker/message/20190927.032457.c1044d4c.en.html
  • https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EED7HM3MFIBAP5OIMJAFJ35JAJABTVSC/
  • https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T3TJW4HPYH3O5HZCWGD6NSHTEBTTAPDC/
  • https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UY6HPRW7MR3KBQ5JFHH6OXM7YCZBJCOB/
  • https://seclists.org/bugtraq/2019/Sep/60
  • https://security.gentoo.org/glsa/202003-47
  • https://usn.ubuntu.com/4141-1/
  • https://www.debian.org/security/2019/dsa-4536
  • http://www.openwall.com/lists/oss-security/2019/09/28/1
  • http://www.openwall.com/lists/oss-security/2019/09/28/2
  • http://www.openwall.com/lists/oss-security/2019/09/28/3
  • http://www.openwall.com/lists/oss-security/2019/09/28/4
  • https://bugs.exim.org/show_bug.cgi?id=2449
  • https://git.exim.org/exim.git/commit/478effbfd9c3cc5a627fc671d4bf94d13670d65f
  • https://lists.exim.org/lurker/message/20190927.032457.c1044d4c.en.html
  • https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EED7HM3MFIBAP5OIMJAFJ35JAJABTVSC/
  • https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T3TJW4HPYH3O5HZCWGD6NSHTEBTTAPDC/
  • https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UY6HPRW7MR3KBQ5JFHH6OXM7YCZBJCOB/
  • https://seclists.org/bugtraq/2019/Sep/60
  • https://security.gentoo.org/glsa/202003-47
  • https://usn.ubuntu.com/4141-1/
  • https://www.debian.org/security/2019/dsa-4536
  • https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-16928

Generated by PoC Generator on 2026-07-02T03:51:50.75022845

Frequently asked questions

What is CVE-2019-16928?

CVE-2019-16928 is a Critical (9.8) vulnerability: Exim 4.92 through 4.92.2 allows remote code execution, a different vulnerability than…. This entry ships a detection-only PoC and a Docker test lab. It is on the CISA Known Exploited Vulnerabilities (KEV) catalog (added 2022-03-03), confirming active exploitation in the wild.

How do I detect CVE-2019-16928?

Run the detection-only PoC included with this entry against your Docker test lab to confirm whether a target is affected; pair it with your own IDS logging.

How do I block or mitigate CVE-2019-16928?

Upgrade to a fixed version per the vendor advisory; the NVD record lists the affected versions. Use the included PoC to verify your remediation.

Is CVE-2019-16928 actively exploited?

Yes. CVE-2019-16928 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, added 2022-03-03, which means it has been exploited in the wild. CISA set a federal remediation deadline of 2022-03-17. Prioritise patching and deploy the detection and prevention rules above.

For authorized security testing and research only. See the full source and NVD record.