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.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | libxml2 | 2.9.3+dfsg1-1.1 | — |
| Debian 13 | libxml2 | 2.9.3+dfsg1-1.1 | — |
| Debian 12 | libxml2 | 2.9.3+dfsg1-1.1 | — |
| Debian 8 | libxml2 | 2.9.1+dfsg1-5+deb8u2 | DSA-3593-1 |
| Debian 7 | libxml2 | 2.8.0+dfsg1-7+wheezy6 | DLA-503-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | libxml2 | 2.9.3+dfsg1-1ubuntu0.1 | USN-2994-1 |
| Ubuntu 14.04 LTS | libxml2 | 2.9.1+dfsg1-3ubuntu4.8 | USN-2994-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | libxml2 +3 | 2.9.1-6.el7_2.3 | RHSA-2016:1292 |
| RHEL 6 | libxml2 +3 | 2.7.6-21.el6_8.1 | RHSA-2016:1292 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP2 | libxml2 +1 | 2.9.4-36.1 | SUSE-SU-2017:1454-1 |
| SLES 12 SP1 | libxml2 +1 | 2.9.1-24.1 | SUSE-SU-2016:1538-1 |
| SLES 12 | libxml2 +1 | 2.9.1-24.1 | SUSE-SU-2016:1538-1 |
| SLES 11 SP4 | libxml2 | 2.7.6-0.44.1 | SUSE-SU-2016:1604-1 |
| SLES 11 SP4 | libxml2-python | 2.7.6-0.44.4 | SUSE-SU-2016:1604-1 |
| SLES 11 SP3 | libxml2 | 2.7.6-0.44.1 | SUSE-SU-2016:1604-1 |
| SLES 11 SP3 | libxml2-python | 2.7.6-0.44.4 | SUSE-SU-2016:1604-1 |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 11 SP2 | libxml2 | 2.7.6-0.44.1 | SUSE-SU-2016:1604-1 |
| SLES 11 SP2 | libxml2-python | 2.7.6-0.44.4 | SUSE-SU-2016:1604-1 |
| SLES for SAP 12 SP2 | libxml2 +1 | 2.9.4-36.1 | SUSE-SU-2017:1454-1 |
| SLES for SAP 12 SP1 | libxml2 +1 | 2.9.1-24.1 | SUSE-SU-2016:1538-1 |
| SLES for SAP 12 | libxml2 +1 | 2.9.1-24.1 | SUSE-SU-2016:1538-1 |
| SLES for SAP 11 SP4 | libxml2 | 2.7.6-0.44.1 | SUSE-SU-2016:1604-1 |
| SLES for SAP 11 SP4 | libxml2-python | 2.7.6-0.44.4 | SUSE-SU-2016:1604-1 |
| SUSE OpenStack Cloud 5 | libxml2 | 2.7.6-0.44.1 | SUSE-SU-2016:1604-1 |
| SUSE OpenStack Cloud 5 | libxml2-python | 2.7.6-0.44.4 | SUSE-SU-2016:1604-1 |
| SUSE Manager Proxy 2.1 | libxml2 | 2.7.6-0.44.1 | SUSE-SU-2016:1604-1 |
| SUSE Manager Proxy 2.1 | libxml2-python | 2.7.6-0.44.4 | SUSE-SU-2016:1604-1 |
| SUSE Manager 2.1 | libxml2 | 2.7.6-0.44.1 | SUSE-SU-2016:1604-1 |
| SUSE Manager 2.1 | libxml2-python | 2.7.6-0.44.4 | SUSE-SU-2016:1604-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | libxml2 | 2.9.4-1.22 | openSUSE-SU-2024:10192-1 |
| openSUSE Tumbleweed | python-libxml2 | 2.9.4-1.4 | openSUSE-SU-2024:10228-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | libxml2 +3 | 2.9.1-6.0.1.el7_2.3 | ELSA-2016-1292 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Exploit-DB 1
- libxml2 - xmlDictAddString Heap Buffer Overread EDB-39491 · dos · Feb 24, 2016 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 12
- RHSA-2016:1292 Red Hat Security Advisory: libxml2 security update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- USN-2994-1 libxml2 vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-3593-1 libxml2 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-503-1 libxml2 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2016:1538-1 Security update for libxml2 SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10228-1 python-libxml2-2.9.4-1.4 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:1604-1 Security update for libxml2 SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10192-1 libxml2-2-2.9.4-1.22 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2017:1454-1 Security update for libxml2 SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2024-3383 libxml2: Mehrere Schwachstellen ermöglichen Ausführen von beliebigem Programmcode mit den Rechten des Dienstes BSI CERT-Bund (WID) · Jun 30, 2025
- WID-SEC-2023-1614 Tenable Security Nessus Network Monitor: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 25, 2023
- ELSA-2016-1292 Important: libxml2 security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jun 23, 2016
References
- http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html
- https://kc.mcafee.com/corporate/index?page=content&id=SB10170
- RHSA-2016:1292 vendor-advisory
- https://bugzilla.gnome.org/show_bug.cgi?id=758605
- http://www.oracle.com/technetwork/topics/security/linuxbulletinjul2016-3090544.html
- https://support.apple.com/HT206567
- 90691 vdb-entry
- DSA-3593 vendor-advisory
- http://xmlsoft.org/news.html
- APPLE-SA-2016-05-16-4 vendor-advisory
- USN-2994-1 vendor-advisory
- https://support.apple.com/HT206566
- https://git.gnome.org/browse/libxml2/commit/?id=a820dbeac29d330bae4be05d9ecd939ad6b4aa33
- http://www.oracle.com/technetwork/topics/security/bulletinjul2016-3090568.html
- https://www.tenable.com/security/tns-2016-18
- APPLE-SA-2016-05-16-3 vendor-advisory
- https://support.apple.com/HT206564
- RHSA-2016:2957 vendor-advisory
- GLSA-201701-37 vendor-advisory
- 1035890 vdb-entry
- APPLE-SA-2016-05-16-2 vendor-advisory
- 1038623 vdb-entry
- https://support.apple.com/HT206568
- APPLE-SA-2016-05-16-1 vendor-advisory