CVE-2016-9840

inftrees.c in zlib 1.2.8 might allow context-dependent attackers to have unspecified impact by leveraging improper pointer arithmetic.

Published: 2017-05-23 Last update: 2026-05-13 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2016-9840 is rated High Risk (65.1/100): CVSS High severity, with high exploitation likelihood (EPSS 9.83%, 93th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. Mandatory action: High exploitation likelihood—assess exposure and prioritize 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-2016-9840

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 2026-06-06 12.52% 9.83% -2.69%
2 2026-05-28 9.72% 12.52% +2.80%
3 2026-05-23 9.72%

Full EPSS history (44 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-9840

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
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:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
2.8 5.9 [email protected]
6.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/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:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
8.6 6.4 [email protected]

Weakness enumeration for CVE-2016-9840

OS Trackers for CVE-2016-9840

vendor priority summary link
debian not yet assigned CVE-2016-9840 not yet assigned priority: Debian including 2 source packages (rsync, zlib), 10 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 10. https://security-tracker.debian.org/tracker/CVE-2016-9840
gentoo normal CVE-2016-9840: 2 GLSA(s) (201701-56, 202007-54), 2 atom(s) (net-misc/rsync, sys-libs/zlib); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2016-9840
redhat low https://access.redhat.com/security/cve/CVE-2016-9840
suse critical CVE-2016-9840 severity critical: SUSE including 597 source package names (0.9.1:libz1-1.2.8-11.1, 1.0.0:libz1-1.2.8-11.1, …), 2838 product×package rows across 361 product lines (Container bci/kiwi, Container caasp/v4/default-http-backend, … (361 product lines)): Fixed 2499, Known Affected 226, Known Not Affected 113. https://www.suse.com/security/cve/CVE-2016-9840/
ubuntu low CVE-2016-9840 low priority: Ubuntu including 4 source packages (klibc, rsync, zlib, zsync), 61 status rows across 23 suites (artful, bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, precise, questing, trusty, upstream, xenial, yakkety, zesty): released 28, not-affected 18, needs-triage 9, ignored 5, needed 1. https://ubuntu.com/security/CVE-2016-9840

Affected software / configurations for CVE-2016-9840

Vendor Product Version Raw CPE
boost boost < 1.78.0 cpe:2.3:a:boost:boost:*:*:*:*:*:*:*:*
zlib zlib >= 1.2.0.6, < 1.2.9 cpe:2.3:a:zlib:zlib:*:*:*:*:*:*:*:*
opensuse leap 42.1 cpe:2.3:o:opensuse:leap:42.1:*:*:*:*:*:*:*
opensuse leap 42.2 cpe:2.3:o:opensuse:leap:42.2:*:*:*:*:*:*:*
opensuse opensuse 13.2 cpe:2.3:o:opensuse:opensuse:13.2:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
canonical ubuntu_linux 16.04 cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:*
canonical ubuntu_linux 18.04 cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:esm:*:*:*
oracle database_server 18c cpe:2.3:a:oracle:database_server:18c:*:*:*:*:*:*:*
oracle jdk 1.6.0 cpe:2.3:a:oracle:jdk:1.6.0:update161:*:*:*:*:*:*
oracle jdk 1.7.0 cpe:2.3:a:oracle:jdk:1.7.0:update151:*:*:*:*:*:*
oracle jdk 1.8.0 cpe:2.3:a:oracle:jdk:1.8.0:update144:*:*:*:*:*:*
oracle jre 1.6.0 cpe:2.3:a:oracle:jre:1.6.0:update161:*:*:*:*:*:*
oracle jre 1.7.0 cpe:2.3:a:oracle:jre:1.7.0:update151:*:*:*:*:*:*
oracle jre 1.8.0 cpe:2.3:a:oracle:jre:1.8.0:update144:*:*:*:*:*:*
oracle mysql >= 5.5.0, <= 5.5.61 cpe:2.3:a:oracle:mysql:*:*:*:*:*:*:*:*
oracle mysql >= 5.6.0, <= 5.6.41 cpe:2.3:a:oracle:mysql:*:*:*:*:*:*:*:*
oracle mysql >= 5.7.0, <= 5.7.23 cpe:2.3:a:oracle:mysql:*:*:*:*:*:*:*:*
oracle mysql >= 8.0.0, <= 8.0.12 cpe:2.3:a:oracle:mysql:*:*:*:*:*:*:*:*
redhat satellite 5.8 cpe:2.3:a:redhat:satellite:5.8:*:*:*:*:*:*:*
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_eus 7.4 cpe:2.3:o:redhat:enterprise_linux_eus:7.4:*:*:*:*:*:*:*
redhat enterprise_linux_eus 7.5 cpe:2.3:o:redhat:enterprise_linux_eus:7.5:*:*:*:*:*:*:*
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_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:*:*:*:*:*:*:*
apple iphone_os < 11 cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*
apple mac_os_x >= 10.0.0, < 10.13.0 cpe:2.3:o:apple:mac_os_x:*:*:*:*:*:*:*:*
apple tvos < 11.0 cpe:2.3:o:apple:tvos:*:*:*:*:*:*:*:*
apple watchos < 4 cpe:2.3:o:apple:watchos:*:*:*:*:*:*:*:*
nodejs node.js >= 4.0.0, <= 4.1.2 cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*
nodejs node.js >= 4.2.0, < 4.8.2 cpe:2.3:a:nodejs:node.js:*:*:*:*:lts:*:*:*
nodejs node.js >= 6.0.0, <= 6.8.1 cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*
nodejs node.js >= 6.9.0, < 6.10.2 cpe:2.3:a:nodejs:node.js:*:*:*:*:lts:*:*:*
nodejs node.js >= 7.0.0, < 7.6.0 cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*

References for CVE-2016-9840

URL Tags
http://lists.opensuse.org/opensuse-updates/2016-12/msg00127.html Third Party Advisory
http://lists.opensuse.org/opensuse-updates/2017-01/msg00050.html Third Party Advisory
http://lists.opensuse.org/opensuse-updates/2017-01/msg00053.html Third Party Advisory
http://www.openwall.com/lists/oss-security/2016/12/05/21 Mailing List Third Party Advisory
http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html Third Party Advisory
http://www.oracle.com/technetwork/security-advisory/cpuoct2018-4428296.html Third Party Advisory
http://www.securityfocus.com/bid/95131 Broken Link
http://www.securitytracker.com/id/1039427 Broken Link
https://access.redhat.com/errata/RHSA-2017:1220 Third Party Advisory
https://access.redhat.com/errata/RHSA-2017:1221 Third Party Advisory
https://access.redhat.com/errata/RHSA-2017:1222 Third Party Advisory
https://access.redhat.com/errata/RHSA-2017:2999 Third Party Advisory
https://access.redhat.com/errata/RHSA-2017:3046 Third Party Advisory
https://access.redhat.com/errata/RHSA-2017:3047 Third Party Advisory
https://access.redhat.com/errata/RHSA-2017:3453 Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1402345 Issue Tracking Third Party Advisory
https://github.com/madler/zlib/commit/6a043145ca6e9c55184013841a67b2fef87e44c0 Patch Third Party Advisory
https://lists.debian.org/debian-lts-announce/2019/03/msg00027.html Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2020/01/msg00030.html Mailing List Third Party Advisory
https://security.gentoo.org/glsa/201701-56 Third Party Advisory
https://security.gentoo.org/glsa/202007-54 Third Party Advisory
https://support.apple.com/HT208112 Third Party Advisory
https://support.apple.com/HT208113 Third Party Advisory
https://support.apple.com/HT208115 Third Party Advisory
https://support.apple.com/HT208144 Third Party Advisory
https://usn.ubuntu.com/4246-1/ Third Party Advisory
https://usn.ubuntu.com/4292-1/ Third Party Advisory
https://wiki.mozilla.org/MOSS/Secure_Open_Source/Completed#zlib Third Party Advisory
https://wiki.mozilla.org/images/0/09/Zlib-report.pdf Broken Link
https://www.oracle.com/security-alerts/cpujul2020.html Third Party Advisory
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