CVE-2016-6306

The certificate parser in OpenSSL before 1.0.1u and 1.0.2 before 1.0.2i might allow remote attackers to cause a denial of service (out-of-bounds read) via crafted certificate operations, related to s3_clnt.c and s3_srvr.c.

Published: 2016-09-26 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-6306 is rated Moderate Risk (63.1/100): CVSS Medium severity, with high exploitation likelihood (EPSS 41.68%, 98th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +32.81% over the last day, indicating growing attacker interest. 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-2016-6306

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 8.87% 41.68% +32.81%
2 2026-05-27 8.13% 8.87% +0.74%
3 2026-03-19 — 8.13% —

Full EPSS history (63 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-6306

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
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.
 2.2 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-2016-6306

OS Trackers for CVE-2016-6306

vendor priority summary link
debian not yet assigned CVE-2016-6306 not yet assigned priority: Debian including 1 source packages (openssl), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2016-6306
gentoo normal CVE-2016-6306: 1 GLSA(s) (201612-16), 1 atom(s) (dev-libs/openssl); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2016-6306
redhat low — https://access.redhat.com/security/cve/CVE-2016-6306
suse low CVE-2016-6306 severity low: SUSE including 533 source package names (MozillaFirefox-68.2.0-78.51.4, MozillaFirefox-branding-SLED-68-21.9.8, …), 997 product×package rows across 108 product lines (HPE Helion OpenStack 8, Image SLES12-SP5-Azure-SAP-BYOS, … (108 product lines)): Fixed 620, Known Not Affected 220, Known Affected 157. https://www.suse.com/security/cve/CVE-2016-6306/
ubuntu medium CVE-2016-6306 medium priority: Ubuntu including 2 source packages (openssl, openssl098), 20 status rows across 10 suites (artful, bionic, cosmic, disco, precise, trusty, upstream, xenial, yakkety, zesty): released 10, DNE 8, ignored 1, needs-triage 1. https://ubuntu.com/security/CVE-2016-6306

Affected software / configurations for CVE-2016-6306

Vendor Product Version Raw CPE
openssl openssl 1.0.1 cpe:2.3:a:openssl:openssl:1.0.1:*:*:*:*:*:*:*
openssl openssl 1.0.1 cpe:2.3:a:openssl:openssl:1.0.1:beta1:*:*:*:*:*:*
openssl openssl 1.0.1 cpe:2.3:a:openssl:openssl:1.0.1:beta2:*:*:*:*:*:*
openssl openssl 1.0.1 cpe:2.3:a:openssl:openssl:1.0.1:beta3:*:*:*:*:*:*
openssl openssl 1.0.1a cpe:2.3:a:openssl:openssl:1.0.1a:*:*:*:*:*:*:*
openssl openssl 1.0.1b cpe:2.3:a:openssl:openssl:1.0.1b:*:*:*:*:*:*:*
openssl openssl 1.0.1c cpe:2.3:a:openssl:openssl:1.0.1c:*:*:*:*:*:*:*
openssl openssl 1.0.1d cpe:2.3:a:openssl:openssl:1.0.1d:*:*:*:*:*:*:*
openssl openssl 1.0.1e cpe:2.3:a:openssl:openssl:1.0.1e:*:*:*:*:*:*:*
openssl openssl 1.0.1f cpe:2.3:a:openssl:openssl:1.0.1f:*:*:*:*:*:*:*
openssl openssl 1.0.1g cpe:2.3:a:openssl:openssl:1.0.1g:*:*:*:*:*:*:*
openssl openssl 1.0.1h cpe:2.3:a:openssl:openssl:1.0.1h:*:*:*:*:*:*:*
openssl openssl 1.0.1i cpe:2.3:a:openssl:openssl:1.0.1i:*:*:*:*:*:*:*
openssl openssl 1.0.1j cpe:2.3:a:openssl:openssl:1.0.1j:*:*:*:*:*:*:*
openssl openssl 1.0.1k cpe:2.3:a:openssl:openssl:1.0.1k:*:*:*:*:*:*:*
openssl openssl 1.0.1l cpe:2.3:a:openssl:openssl:1.0.1l:*:*:*:*:*:*:*
openssl openssl 1.0.1m cpe:2.3:a:openssl:openssl:1.0.1m:*:*:*:*:*:*:*
openssl openssl 1.0.1n cpe:2.3:a:openssl:openssl:1.0.1n:*:*:*:*:*:*:*
openssl openssl 1.0.1o cpe:2.3:a:openssl:openssl:1.0.1o:*:*:*:*:*:*:*
openssl openssl 1.0.1p cpe:2.3:a:openssl:openssl:1.0.1p:*:*:*:*:*:*:*
openssl openssl 1.0.1q cpe:2.3:a:openssl:openssl:1.0.1q:*:*:*:*:*:*:*
openssl openssl 1.0.1r cpe:2.3:a:openssl:openssl:1.0.1r:*:*:*:*:*:*:*
openssl openssl 1.0.1s cpe:2.3:a:openssl:openssl:1.0.1s:*:*:*:*:*:*:*
openssl openssl 1.0.1t cpe:2.3:a:openssl:openssl:1.0.1t:*:*:*:*:*:*:*
hp icewall_federation_agent 3.0 cpe:2.3:a:hp:icewall_federation_agent:3.0:*:*:*:*:*:*:*
hp icewall_mcrp 3.0 cpe:2.3:a:hp:icewall_mcrp:3.0:*:*:*:*:*:*:*
hp icewall_sso 10.0 cpe:2.3:a:hp:icewall_sso:10.0:*:*:*:certd:*:*:*
hp icewall_sso 10.0 cpe:2.3:a:hp:icewall_sso:10.0:*:*:*:dfw:*:*:*
hp icewall_sso_agent_option 10.0 cpe:2.3:a:hp:icewall_sso_agent_option:10.0:*:*:*:*:*:*:*
novell suse_linux_enterprise_module_for_web_scripting 12.0 cpe:2.3:o:novell:suse_linux_enterprise_module_for_web_scripting:12.0:*:*:*:*:*:*:*
openssl openssl 1.0.2 cpe:2.3:a:openssl:openssl:1.0.2:*:*:*:*:*:*:*
openssl openssl 1.0.2 cpe:2.3:a:openssl:openssl:1.0.2:beta1:*:*:*:*:*:*
openssl openssl 1.0.2 cpe:2.3:a:openssl:openssl:1.0.2:beta2:*:*:*:*:*:*
openssl openssl 1.0.2 cpe:2.3:a:openssl:openssl:1.0.2:beta3:*:*:*:*:*:*
openssl openssl 1.0.2a cpe:2.3:a:openssl:openssl:1.0.2a:*:*:*:*:*:*:*
openssl openssl 1.0.2b cpe:2.3:a:openssl:openssl:1.0.2b:*:*:*:*:*:*:*
openssl openssl 1.0.2c cpe:2.3:a:openssl:openssl:1.0.2c:*:*:*:*:*:*:*
openssl openssl 1.0.2d cpe:2.3:a:openssl:openssl:1.0.2d:*:*:*:*:*:*:*
openssl openssl 1.0.2e cpe:2.3:a:openssl:openssl:1.0.2e:*:*:*:*:*:*:*
openssl openssl 1.0.2f cpe:2.3:a:openssl:openssl:1.0.2f:*:*:*:*:*:*:*
openssl openssl 1.0.2h cpe:2.3:a:openssl:openssl:1.0.2h:*:*:*:*:*:*:*
nodejs node.js >= 0.10.0, < 0.10.47 cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*
nodejs node.js >= 0.12.0, < 0.12.16 cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*
nodejs node.js >= 4.0.0, <= 4.1.2 cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*
nodejs node.js >= 4.2.0, < 4.6.0 cpe:2.3:a:nodejs:node.js:*:*:*:*:lts:*:*:*
nodejs node.js >= 5.0.0, <= 5.12.0 cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*
nodejs node.js >= 6.0.0, < 6.7.0 cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*
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:*:*:*:-:*:*:*
canonical ubuntu_linux 14.04 cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:*
canonical ubuntu_linux 16.04 cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:*

References for CVE-2016-6306

URL Tags
http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10759 Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-09/msg00022.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-09/msg00023.html Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-09/msg00024.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-09/msg00031.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-10/msg00005.html Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-10/msg00011.html Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-10/msg00012.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-10/msg00013.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-10/msg00021.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-10/msg00029.html Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2017-10/msg00010.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2017-10/msg00011.html Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2018-02/msg00032.html Mailing List Third Party Advisory
http://rhn.redhat.com/errata/RHSA-2016-1940.html Third Party Advisory
http://seclists.org/fulldisclosure/2017/Jul/31 Mailing List Third Party Advisory
http://www-01.ibm.com/support/docview.wss?uid=swg21995039 Third Party Advisory
http://www.debian.org/security/2016/dsa-3673 Third Party Advisory
http://www.huawei.com/en/psirt/security-advisories/huawei-sa-20170322-01-openssl-en Third Party Advisory
http://www.oracle.com/technetwork/security-advisory/cpuapr2018-3678067.html Patch Third Party Advisory
http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.html Patch Third Party Advisory
http://www.oracle.com/technetwork/security-advisory/cpujul2017-3236622.html Patch Third Party Advisory
http://www.oracle.com/technetwork/security-advisory/cpuoct2016-2881722.html Patch Third Party Advisory
http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html Patch Third Party Advisory
http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2016-3090545.html Third Party Advisory
http://www.oracle.com/technetwork/topics/security/ovmbulletinoct2016-3090547.html Third Party Advisory
http://www.securityfocus.com/bid/93153 Third Party Advisory VDB Entry
http://www.securitytracker.com/id/1036885 Third Party Advisory VDB Entry
http://www.ubuntu.com/usn/USN-3087-1 Third Party Advisory
http://www.ubuntu.com/usn/USN-3087-2 Third Party Advisory
https://access.redhat.com/errata/RHSA-2018:2185 Third Party Advisory
https://access.redhat.com/errata/RHSA-2018:2186 Third Party Advisory
https://access.redhat.com/errata/RHSA-2018:2187 Third Party Advisory
https://bto.bluecoat.com/security-advisory/sa132 Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
https://git.openssl.org/?p=openssl.git%3Ba=commit%3Bh=52e623c4cb06fffa9d5e75c60b34b4bc130b12e9
https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-c05302448 Third Party Advisory
https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05302448 Third Party Advisory
https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA40312 Third Party Advisory
https://kc.mcafee.com/corporate/index?page=content&id=SB10215 Third Party Advisory
https://nodejs.org/en/blog/vulnerability/september-2016-security-releases/ Vendor Advisory
https://security.FreeBSD.org/advisories/FreeBSD-SA-16:26.openssl.asc Third Party Advisory
https://security.gentoo.org/glsa/201612-16 Third Party Advisory
https://support.f5.com/csp/article/K90492697 Third Party Advisory
https://support.hpe.com/hpsc/doc/public/display?docLocale=en&docId=emr_na-hpesbhf03856en_us Third Party Advisory
https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03856en_us Third Party Advisory
https://www.arista.com/en/support/advisories-notices/security-advisories/1749-security-advisory-24 Third Party Advisory
https://www.openssl.org/news/secadv/20160922.txt Vendor Advisory
https://www.oracle.com/security-alerts/cpuapr2020.html Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2020.html Third Party Advisory
https://www.oracle.com/security-alerts/cpujul2020.html Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2020.html Third Party Advisory
https://www.oracle.com/technetwork/security-advisory/cpujul2019-5072835.html Patch Third Party Advisory
https://www.tenable.com/security/tns-2016-16 Third Party Advisory
https://www.tenable.com/security/tns-2016-20 Third Party Advisory
https://www.tenable.com/security/tns-2016-21 Third Party Advisory
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