CVE-2016-6304

Multiple memory leaks in t1_lib.c in OpenSSL before 1.0.1u, 1.0.2 before 1.0.2i, and 1.1.0 before 1.1.0a allow remote attackers to cause a denial of service (memory consumption) via large OCSP Status Request extensions.

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-2016-6304 is rated High Risk (69.7/100): CVSS High severity, with high exploitation likelihood (EPSS 63.03%, 99th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +34.95% 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-2016-6304

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 28.07% 63.03% +34.95%
2 2026-06-04 18.04% 28.07% +10.03%
3 2026-03-22 — 18.04% —

Full EPSS history (58 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-6304

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/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: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: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.
 3.9 3.6 [email protected]
7.8 2.0 HIGH
AV:N/AC:L/Au:N/C:N/I:N/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:C)
Complete availability impact.
 10.0 6.9 [email protected]

Weakness enumeration for CVE-2016-6304

OS Trackers for CVE-2016-6304

vendor priority summary link
debian not yet assigned CVE-2016-6304 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-2016-6304
gentoo normal CVE-2016-6304: 1 GLSA(s) (201612-16), 1 atom(s) (dev-libs/openssl); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2016-6304
redhat high — https://access.redhat.com/security/cve/CVE-2016-6304
suse medium CVE-2016-6304 severity moderate: SUSE including 542 source package names (MozillaFirefox-68.2.0-78.51.4, MozillaFirefox-branding-SLED-68-21.9.8, …), 1005 product×package rows across 109 product lines (HPE Helion OpenStack 8, Image SLES12-SP5-Azure-SAP-BYOS, … (109 product lines)): Fixed 626, Known Not Affected 222, Known Affected 157. https://www.suse.com/security/cve/CVE-2016-6304/
ubuntu high CVE-2016-6304 high 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-2016-6304

Affected software / configurations for CVE-2016-6304

Vendor Product Version Raw CPE
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:*:*:*:*:*:*:*
openssl openssl 1.1.0 cpe:2.3:a:openssl:openssl:1.1.0:*:*:*:*:*:*:*
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:*:*:*:*:*:*:*
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, < 4.6.0 cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*
nodejs node.js >= 6.0.0, < 6.7.0 cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*
novell suse_linux_enterprise_module_for_web_scripting 12.0 cpe:2.3:o:novell:suse_linux_enterprise_module_for_web_scripting:12.0:*:*:*:*:*:*:*

References for CVE-2016-6304

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 Mailing List 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 Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-10/msg00011.html Mailing List 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 Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-11/msg00021.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-11/msg00027.html Mailing List 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 Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2018-02/msg00032.html Mailing List Third Party Advisory
http://packetstormsecurity.com/files/139091/OpenSSL-x509-Parsing-Double-Free-Invalid-Free.html Third Party Advisory VDB Entry
http://rhn.redhat.com/errata/RHSA-2016-1940.html Third Party Advisory
http://rhn.redhat.com/errata/RHSA-2016-2802.html Third Party Advisory
http://rhn.redhat.com/errata/RHSA-2017-1415.html Third Party Advisory
http://rhn.redhat.com/errata/RHSA-2017-1659.html Third Party Advisory
http://seclists.org/fulldisclosure/2016/Dec/47 Mailing List Third Party Advisory
http://seclists.org/fulldisclosure/2016/Oct/62 Mailing List 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/93150 Third Party Advisory VDB Entry
http://www.securitytracker.com/id/1036878 Third Party Advisory VDB Entry
http://www.securitytracker.com/id/1037640 Third Party Advisory VDB Entry
http://www.splunk.com/view/SP-CAAAPSV Third Party Advisory
http://www.splunk.com/view/SP-CAAAPUE Third Party Advisory
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-2017:1413 Third Party Advisory
https://access.redhat.com/errata/RHSA-2017:1414 Third Party Advisory
https://access.redhat.com/errata/RHSA-2017:1658 Third Party Advisory
https://access.redhat.com/errata/RHSA-2017:1801 Third Party Advisory
https://access.redhat.com/errata/RHSA-2017:1802 Third Party Advisory
https://access.redhat.com/errata/RHSA-2017:2493 Third Party Advisory
https://access.redhat.com/errata/RHSA-2017:2494 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=2c0d295e26306e15a92eb23a84a1802005c1c137
https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA40312 Third Party Advisory
https://kc.mcafee.com/corporate/index?page=content&id=SB10171 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/ Third Party 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://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.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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