CVE-2019-14243

mastercactapus proxyprotocol vulnerable to denial of service

7.5 HighFix available

headerv2.go in mastercactapus proxyprotocol before 0.0.2, as used in the mastercactapus caddy-proxyprotocol plugin through 0.0.2 for Caddy, allows remote attackers to cause a denial of service (webserver panic and daemon crash) via a crafted HAProxy PROXY v2 request with truncated source/destination address data.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: High

Exploit likelihood

4.29%Up 1.9 points since Apr 14, 2021

What each source reports

NVD Score used 7.5

Record: CVE-2019-14243
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0: 5.0 MediumAV:N/AC:L/Au:N/C:N/I:N/A:P
Weakness: CWE-20
Updated: 2026-11-02

CVE List No score

Record: CVE-2019-14243
Updated: 2026-11-02

EUVDEUVD-2022-3110 No score

Record: EUVD-2022-3110
Updated: 2026-11-03

GitHub AdvisoriesGHSA-85c5-ccm8-vr96 7.5

mastercactapus proxyprotocol vulnerable to denial of service

Record: GHSA-85c5-ccm8-vr96
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-20
Updated: 2026-11-02

OSV 7.5

Record: CVE-2019-14243
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVGHSA-85c5-ccm8-vr96 7.5

mastercactapus proxyprotocol vulnerable to denial of service

Record: GHSA-85c5-ccm8-vr96
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-20
Updated: 2026-11-02

OSVGO-2023-1923 No score

Panic when handling invalid HAProxy PROXY v2 request in github.com/mastercactapus/proxyprotocol

Panic when handling invalid HAProxy PROXY v2 request in github.com/mastercactapus/proxyprotocol

Record: GO-2023-1923
Updated: 2026-11-02

Affected products

haproxy proxyprotocol

Affected packages

Affected packages
Package	Affected	Fixed
`github.com/mastercactapus/proxyprotocol` Go	before 0.0.2	0.0.2

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2019-14243 is a high vulnerability (CVSS 7.5) in Haproxy Proxyprotocol, published July 23, 2019. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 4.29%, the 91st percentile. Fixed in github.com/mastercactapus/proxyprotocol 0.0.2.