---
id: CVE-2016-4472
title: >-
  The overflow protection in Expat is removed by compilers with certain
  optimization settings, which allows remote attackers to cause a denial of
  service (crash) or possibly execute arbitrary code via crafted XML data
summary: >-
  The overflow protection in Expat is removed by compilers with certain
  optimization settings, which allows remote attackers to cause a denial of
  service (crash) or possibly execute arbitrary code via crafted XML data. 
  NOTE: this vulnerab…
severity: high
cvss: 8.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-119
vendor: libexpat_project
product: libexpat
affected:
  - libexpat <= 2.1.1
  - ubuntu_linux = 12.04
  - policy_auditor < 6.5.1
  - 'python >= 2.7.0, < 2.7.15'
  - 'python >= 3.3.0, < 3.3.7'
  - 'python >= 3.4.0, < 3.4.7'
  - 'python >= 3.5.0, < 3.5.4'
  - 'python >= 3.6.0, < 3.6.2'
patched:
  - policy_auditor 6.5.1
  - python 3.6.2
published: '2016-06-30'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T21:17:05.260'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2016-4472'
references:
  - url: 'http://www.securityfocus.com/bid/91528'
    label: secalert@redhat.com
  - url: 'http://www.ubuntu.com/usn/USN-3013-1'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=1344251'
    label: secalert@redhat.com
  - url: 'https://kc.mcafee.com/corporate/index?page=content&id=SB10365'
    label: secalert@redhat.com
  - url: 'https://security.gentoo.org/glsa/201701-21'
    label: secalert@redhat.com
  - url: >-
      https://sourceforge.net/p/expat/code_git/ci/f0bec73b018caa07d3e75ec8dd967f3785d71bde
    label: secalert@redhat.com
  - url: 'https://www.tenable.com/security/tns-2016-20'
    label: secalert@redhat.com
  - url: 'http://www.securityfocus.com/bid/91528'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'http://www.ubuntu.com/usn/USN-3013-1'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=1344251'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://kc.mcafee.com/corporate/index?page=content&id=SB10365'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://security.gentoo.org/glsa/201701-21'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://sourceforge.net/p/expat/code_git/ci/f0bec73b018caa07d3e75ec8dd967f3785d71bde
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.tenable.com/security/tns-2016-20'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.11946
epssPercentile: 0.96033
ingestedAt: '2026-10-08T22:11:53.690Z'
---

## Overview

The overflow protection in Expat is removed by compilers with certain optimization settings, which allows remote attackers to cause a denial of service (crash) or possibly execute arbitrary code via crafted XML data.  NOTE: this vulnerability exists because of an incomplete fix for CVE-2015-1283 and CVE-2015-2716.

## Affected

- `libexpat <= 2.1.1`
- `ubuntu_linux = 12.04`
- `policy_auditor < 6.5.1`
- `python >= 2.7.0, < 2.7.15`
- `python >= 3.3.0, < 3.3.7`
- `python >= 3.4.0, < 3.4.7`
- `python >= 3.5.0, < 3.5.4`
- `python >= 3.6.0, < 3.6.2`

## Remediation

Upgrade past the affected range:

- `policy_auditor 6.5.1`
- `python 3.6.2`