---
id: CVE-1999-1301
title: >-
  A design flaw in the Z-Modem protocol allows the remote sender of a file to
  execute arbitrary programs on the client, as implemented in rz in the rzsz
  module of FreeBSD before 2.1.5, and possibly other programs.
summary: >-
  A design flaw in the Z-Modem protocol allows the remote sender of a file to
  execute arbitrary programs on the client, as implemented in rz in the rzsz
  module of FreeBSD before 2.1.5, and possibly other programs.
severity: high
cvss: 7.5
cvssVector: 'AV:N/AC:L/Au:N/C:P/I:P/A:P'
published: '1996-07-16'
updated: '2026-06-16'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-1999-1301'
references:
  - url: >-
      ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/advisories/old/FreeBSD-SA-96:17.rzsz.asc
    label: cve@mitre.org
  - url: 'http://ciac.llnl.gov/ciac/bulletins/g-31.shtml'
    label: cve@mitre.org
  - url: 'http://www.iss.net/security_center/static/7540.php'
    label: cve@mitre.org
  - url: >-
      ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/advisories/old/FreeBSD-SA-96:17.rzsz.asc
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'http://ciac.llnl.gov/ciac/bulletins/g-31.shtml'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'http://www.iss.net/security_center/static/7540.php'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.01316
epssPercentile: 0.69543
ingestedAt: '2026-06-22T15:59:08.083Z'
---

## Overview

A design flaw in the Z-Modem protocol allows the remote sender of a file to execute arbitrary programs on the client, as implemented in rz in the rzsz module of FreeBSD before 2.1.5, and possibly other programs.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.