CVE-2016-1839

Exp

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.

Published: 2016-05-20 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-1839 is rated High Exploit Risk (69.7/100): CVSS Medium severity, with high exploitation likelihood (EPSS 7.35%, 94th percentile). 2 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2016-1839

EDB-ID Source Kind Published Link
39491 exploit_db edb 2016-02-24 Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2016-1839

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-26 7.41% 7.35% -0.06%
2 2026-06-15 4.55% 7.41% +2.86%
3 2026-05-12 — 4.55% —

Full EPSS history (19 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-1839

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.0 MEDIUM
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2016-1839

OS Trackers for CVE-2016-1839

vendor priority summary link
debian not yet assigned CVE-2016-1839 not yet assigned priority: Debian including 1 source packages (libxml2), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2016-1839
gentoo normal CVE-2016-1839: 1 GLSA(s) (201701-37), 1 atom(s) (dev-libs/libxml2); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2016-1839
redhat medium — https://access.redhat.com/security/cve/CVE-2016-1839
suse medium CVE-2016-1839 severity moderate: SUSE including 137 source package names (0.9.1:libxml2-2-2.9.4-36.1, 1.0.0:libxml2-2-2.9.4-36.1, …), 271 product×package rows across 96 product lines (Container caasp/v4/default-http-backend, Container caasp/v4/dnsmasq-nanny, … (96 product lines)): Fixed 271. https://www.suse.com/security/cve/CVE-2016-1839/
ubuntu medium CVE-2016-1839 medium priority: Ubuntu including 1 source packages (libxml2), 7 status rows across 7 suites (precise, trusty, upstream, wily, xenial, yakkety, zesty): released 5, not-affected 2. https://ubuntu.com/security/CVE-2016-1839

Affected software / configurations for CVE-2016-1839

Vendor Product Version Raw CPE
apple iphone_os < 9.3.2 cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*
apple mac_os_x < 10.11.5 cpe:2.3:o:apple:mac_os_x:*:*:*:*:*:*:*:*
apple tvos < 9.2.1 cpe:2.3:o:apple:tvos:*:*:*:*:*:*:*:*
apple watchos < 2.2.1 cpe:2.3:o:apple:watchos:*:*:*:*:*:*:*:*
canonical ubuntu_linux 12.04 cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 14.04 cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 15.10 cpe:2.3:o:canonical:ubuntu_linux:15.10:*:*:*:*:*:*:*
canonical ubuntu_linux 16.04 cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
redhat enterprise_linux_desktop 6.0 cpe:2.3:o:redhat:enterprise_linux_desktop:6.0:*:*:*:*:*:*:*
redhat enterprise_linux_desktop 7.0 cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:*
redhat enterprise_linux_server 6.0 cpe:2.3:o:redhat:enterprise_linux_server:6.0:*:*:*:*:*:*:*
redhat enterprise_linux_server 7.0 cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:*
redhat enterprise_linux_server_aus 7.2 cpe:2.3:o:redhat:enterprise_linux_server_aus:7.2:*:*:*:*:*:*:*
redhat enterprise_linux_server_aus 7.3 cpe:2.3:o:redhat:enterprise_linux_server_aus:7.3:*:*:*:*:*:*:*
redhat enterprise_linux_server_aus 7.4 cpe:2.3:o:redhat:enterprise_linux_server_aus:7.4:*:*:*:*:*:*:*
redhat enterprise_linux_server_aus 7.6 cpe:2.3:o:redhat:enterprise_linux_server_aus:7.6:*:*:*:*:*:*:*
redhat enterprise_linux_server_eus 7.2 cpe:2.3:o:redhat:enterprise_linux_server_eus:7.2:*:*:*:*:*:*:*
redhat enterprise_linux_server_eus 7.3 cpe:2.3:o:redhat:enterprise_linux_server_eus:7.3:*:*:*:*:*:*:*
redhat enterprise_linux_server_eus 7.4 cpe:2.3:o:redhat:enterprise_linux_server_eus:7.4:*:*:*:*:*:*:*
redhat enterprise_linux_server_eus 7.5 cpe:2.3:o:redhat:enterprise_linux_server_eus:7.5:*:*:*:*:*:*:*
redhat enterprise_linux_server_eus 7.6 cpe:2.3:o:redhat:enterprise_linux_server_eus:7.6:*:*:*:*:*:*:*
redhat enterprise_linux_server_tus 7.2 cpe:2.3:o:redhat:enterprise_linux_server_tus:7.2:*:*:*:*:*:*:*
redhat enterprise_linux_server_tus 7.3 cpe:2.3:o:redhat:enterprise_linux_server_tus:7.3:*:*:*:*:*:*:*
redhat enterprise_linux_server_tus 7.6 cpe:2.3:o:redhat:enterprise_linux_server_tus:7.6:*:*:*:*:*:*:*
redhat enterprise_linux_workstation 6.0 cpe:2.3:o:redhat:enterprise_linux_workstation:6.0:*:*:*:*:*:*:*
redhat enterprise_linux_workstation 7.0 cpe:2.3:o:redhat:enterprise_linux_workstation:7.0:*:*:*:*:*:*:*
mcafee web_gateway >= 7.5.0.0, <= 7.5.2.10 cpe:2.3:a:mcafee:web_gateway:*:*:*:*:*:*:*:*
mcafee web_gateway >= 7.6.0.0, <= 7.6.2.3 cpe:2.3:a:mcafee:web_gateway:*:*:*:*:*:*:*:*
xmlsoft libxml2 < 2.9.4 cpe:2.3:a:xmlsoft:libxml2:*:*:*:*:*:*:*:*

References for CVE-2016-1839

URL Tags
http://lists.apple.com/archives/security-announce/2016/May/msg00001.html Mailing List Vendor Advisory
http://lists.apple.com/archives/security-announce/2016/May/msg00002.html Mailing List Vendor Advisory
http://lists.apple.com/archives/security-announce/2016/May/msg00003.html Mailing List Vendor Advisory
http://lists.apple.com/archives/security-announce/2016/May/msg00004.html Mailing List Vendor Advisory
http://rhn.redhat.com/errata/RHSA-2016-2957.html Third Party Advisory
http://www.oracle.com/technetwork/topics/security/bulletinjul2016-3090568.html Third Party Advisory
http://www.oracle.com/technetwork/topics/security/linuxbulletinjul2016-3090544.html Third Party Advisory
http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html Third Party Advisory
http://www.securityfocus.com/bid/90691 Third Party Advisory VDB Entry
http://www.securitytracker.com/id/1035890 Third Party Advisory VDB Entry
http://www.securitytracker.com/id/1038623 Third Party Advisory VDB Entry
http://www.ubuntu.com/usn/USN-2994-1 Third Party Advisory
http://xmlsoft.org/news.html Release Notes Vendor Advisory
https://access.redhat.com/errata/RHSA-2016:1292 Third Party Advisory
https://bugzilla.gnome.org/show_bug.cgi?id=758605 Exploit Issue Tracking Third Party Advisory
https://git.gnome.org/browse/libxml2/commit/?id=a820dbeac29d330bae4be05d9ecd939ad6b4aa33 Patch Third Party Advisory
https://kc.mcafee.com/corporate/index?page=content&id=SB10170 Patch Third Party Advisory
https://security.gentoo.org/glsa/201701-37 Third Party Advisory
https://support.apple.com/HT206564 Vendor Advisory
https://support.apple.com/HT206566 Vendor Advisory
https://support.apple.com/HT206567 Vendor Advisory
https://support.apple.com/HT206568 Vendor Advisory
https://www.debian.org/security/2016/dsa-3593 Third Party Advisory
https://www.tenable.com/security/tns-2016-18 Third Party Advisory
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