CVE-2016-4449

XML external entity (XXE) vulnerability in the xmlStringLenDecodeEntities function in parser.c in libxml2 before 2.9.4, when not in validating mode, allows context-dependent attackers to read arbitrary files or cause a denial of service (resource consumption) via unspecified vectors.

Published: 2016-06-09 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-4449 is rated Moderate Risk (55.7/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.67%). EPSS rose +1.54% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

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

Exploit prediction scoring system (EPSS) score for CVE-2016-4449

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 2026-06-15 0.12% 1.67% +1.54%
2 2026-05-12 0.18% 0.12% -0.06%
3 2026-05-11 — 0.18% —

Full EPSS history (17 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-4449

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.1 3.0 HIGH
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/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:H)
Serious risk that confidential data gets exposed in a big 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 5.2 [email protected]
5.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/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:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 4.9 [email protected]

Weakness enumeration for CVE-2016-4449

OS Trackers for CVE-2016-4449

vendor priority summary link
debian not yet assigned CVE-2016-4449 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-2016-4449
redhat medium — https://access.redhat.com/security/cve/CVE-2016-4449
suse medium CVE-2016-4449 severity moderate: SUSE including 19 source package names (libxml2-2-2.9.1-24.1, libxml2-2-32bit-2.9.1-24.1, …), 76 product×package rows across 20 product lines (SUSE Liberty Linux 7, SUSE Linux Enterprise Desktop 12, … (20 product lines)): Fixed 76. https://www.suse.com/security/cve/CVE-2016-4449/
ubuntu low CVE-2016-4449 low 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-2016-4449

Affected software / configurations for CVE-2016-4449

Vendor Product Version Raw CPE
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
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:*:*:*
xmlsoft libxml2 <= 2.9.3 cpe:2.3:a:xmlsoft:libxml2:*:*:*:*:*:*:*:*

References for CVE-2016-4449

URL Tags
http://jvn.jp/en/jp/JVN17535578/index.html
http://jvndb.jvn.jp/en/contents/2017/JVNDB-2017-000066.html
http://lists.apple.com/archives/security-announce/2016/Jul/msg00000.html
http://lists.apple.com/archives/security-announce/2016/Jul/msg00001.html
http://lists.apple.com/archives/security-announce/2016/Jul/msg00002.html
http://lists.apple.com/archives/security-announce/2016/Jul/msg00003.html
http://lists.apple.com/archives/security-announce/2016/Jul/msg00005.html
http://rhn.redhat.com/errata/RHSA-2016-2957.html
http://www.openwall.com/lists/oss-security/2016/05/25/2
http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.html
http://www.oracle.com/technetwork/topics/security/bulletinjul2016-3090568.html
http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html
http://www.securityfocus.com/bid/90865
http://www.securitytracker.com/id/1036348
http://www.slackware.com/security/viewer.php?l=slackware-security&y=2016&m=slackware-security.404722
http://www.ubuntu.com/usn/USN-2994-1
http://xmlsoft.org/news.html
https://access.redhat.com/errata/RHSA-2016:1292
https://git.gnome.org/browse/libxml2/commit/?id=b1d34de46a11323fccffa9fadeb33be670d602f5 Vendor Advisory
https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05194709
https://kc.mcafee.com/corporate/index?page=content&id=SB10170
https://support.apple.com/HT206899
https://support.apple.com/HT206901
https://support.apple.com/HT206902
https://support.apple.com/HT206903
https://support.apple.com/HT206904
https://support.apple.com/HT206905
https://support.cybozu.com/ja-jp/article/9735
https://www.debian.org/security/2016/dsa-3593
https://www.tenable.com/security/tns-2016-18
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