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Public proof of conceptFix available

CVE-2016-1839

A public proof of concept exists; no exploitation attested.

  • Published2016-05-20
  • WeaknessCWE-125

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

The xmlDictAddString function in libxml2 before 2.9.4, as used in Apple iOS before 9.3.2, OS X before 10.11.5, tvOS before 9.2.1, and watchOS before 2.2.1, allows remote attackers to cause a denial of service (heap-based buffer over-read) via a crafted XML document.

Timeline

dates in UTC
  1. 2016-02-24Exploit-DB entryExploit-DB

Versions per branch

NVD
Redhat enterprise linux server eus
BranchAffectedFixed in
7.2= 7.2no fix published
7.3= 7.3no fix published
7.4= 7.4no fix published
7.5= 7.5no fix published
7.6= 7.6no fix published
Canonical ubuntu linux
BranchAffectedFixed in
12.4= 12.04no fix published
14.4= 14.04no fix published
15.10= 15.10no fix published
16.4= 16.04no fix published
Redhat enterprise linux server aus
BranchAffectedFixed in
7.2= 7.2no fix published
7.3= 7.3no fix published
7.4= 7.4no fix published
7.6= 7.6no fix published

11 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • libxml2Ubuntu:16.04:LTSall versions · fixed in 2.9.3+dfsg1-1ubuntu0.1
  • libxml2Ubuntu:14.04:LTSall versions · fixed in 2.9.1+dfsg1-3ubuntu4.8
  • libxml2SUSE:OpenStack Cloud 5all versions · fixed in 2.7.6-0.44.1
  • libxml2SUSE:Manager Proxy 2.1all versions · fixed in 2.7.6-0.44.1
  • libxml2SUSE:Manager 2.1all versions · fixed in 2.7.6-0.44.1
  • libxml2SUSE:Linux Enterprise Software Development Kit 12 SP2all versions · fixed in 2.9.4-36.1
  • libxml2SUSE:Linux Enterprise Software Development Kit 12 SP1all versions · fixed in 2.9.1-24.1
  • libxml2SUSE:Linux Enterprise Software Development Kit 12all versions · fixed in 2.9.1-24.1

41 more package ranges on OSV.dev

Vendor advisories

  • CVE-2016-1839 Red Hat Product Security145 products fixed · 2 known affected

    libxml2: Heap-based buffer overread in xmlDictAddString

    libxml2.src as a component of Red Hat Enterprise Linux 5 · libxml2.src as a component of Red Hat JBoss Enterprise Web Server 3

  • RHSA-2016:2957 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP 2.4.23 Release

  • RHSA-2016:1292 Red Hat Product Security144 products fixed

    Red Hat Security Advisory: libxml2 security update

Full record on NVD

Fix

  1. Vendor fix Red Hat Product Security RHSA-2016:2957 · 1 productThe References section of this erratum contains a download link (you must log in to download the update). Before applying the update, back up your existing Red Hat JBoss Web Server installation (including all applications and configuration files). After installing the updated packages, the httpd d…
  2. Vendor fix Red Hat Product Security RHSA-2016:1292 · 144 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 For the update to take effect, all applications linked to the libxml2 library must be restarted, or the system rebooted.
  3. No fix available, says the vendor Red Hat Product Security CVE-2016-1839 · 1 productAffected
  4. No fix planned, says the vendor Red Hat Product Security CVE-2016-1839 · 1 productWill not fix

Advisories and patches

Detection

read 2026-11-09 09:28 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
EDB-39491
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Published
2016-05-20
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-768p-297v-97cm

Frequently asked questions

What is CVE-2016-1839?

The xmlDictAddString function in libxml2 before 2.9.4, as used in Apple iOS before 9.3.2, OS X before 10.11.5, tvOS before 9.2.1, and watchOS before 2.2.1, allows remote attackers to cause a denial of service (heap-based buffer over-read) via a crafted XML document.

Is CVE-2016-1839 actively exploited?

Active exploitation of CVE-2016-1839 has not been confirmed. Its EPSS score was 7.3% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2016-1839?

CVE-2016-1839 has a CVSS v3 base score of 5.5 (MEDIUM severity), with vector string CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

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