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Fencer Intel
high 7.5

CVE-2016-2181 in the critical feed json

The Anti-Replay feature in the DTLS implementation in OpenSSL before 1.1.0 mishandles early use of a new epoch number in conjunction with a…

published 2016-09-16 10 y ago modified 2026-06-17 4 mo ago also EUVD-2016-3266

cvss
7.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
22.6%
EPSS 22.6% chance of exploitation in 30 days, percentile 97%
public exploits
0
none known

Summary

The Anti-Replay feature in the DTLS implementation in OpenSSL before 1.1.0 mishandles early use of a new epoch number in conjunction with a large sequence number, which allows remote attackers to cause a denial of service (false-positive packet drops) via spoofed DTLS records, related to rec_layer_d1.c and ssl3_record.c.

Patch / fix

  • openssl Debian 14, Debian 13, Debian 12 1.0.2i-1

debian advisories DEBIAN-CVE-2016-2181

  • openssl Ubuntu 14.04 LTS 1.0.1f-1ubuntu2.20
  • openssl Ubuntu 16.04 LTS 1.0.2g-1ubuntu4.4

ubuntu advisories UBUNTU-CVE-2016-2181

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • openssl RHEL 6 1.0.1e-48.el6_8.3
  • openssl RHEL 7 1:1.0.1e-51.el7_2.7
  • openssl-libs RHEL 7 1:1.0.1e-51.el7_2.7
  • openssl-perl RHEL 6 1.0.1e-48.el6_8.3
  • openssl-perl RHEL 7 1:1.0.1e-51.el7_2.7

red hat advisories RHSA-2016:1940

  • compat-openssl098 SLES for SAP 12 SP1, SLED 12 SP1, SLE Module for Legacy 12 0.9.8j-102.1
  • openssl1 SLES 11-SECURITY 1.0.1g-0.52.1
  • openssl Studio Onsite 1.3, SLES for SAP 11 SP4, SLES 11 SP4 +8 more 0.9.8j-0.102.2
  • openssl SLES for SAP 12 SP1, SLES 12 SP1, SLED 12 SP1 +1 more 1.0.1i-52.1
  • openssl SLES for SAP 12, SLES 12-LTSS 1.0.1i-27.21.1

suse advisories SUSE-SU-2016:2468-1SUSE-SU-2016:2469-1SUSE-SU-2016:2458-1SUSE-SU-2016:2394-1SUSE-SU-2016:2387-1

  • openssl-1_1 openSUSE Tumbleweed 1.1.1l-1.2

opensuse advisories openSUSE-SU-2024:11127-1

  • openssl Alpine 3.8, Alpine 3.7, Alpine 3.6 +4 more 1.0.2h-r4

alpine advisories ALPINE-CVE-2016-2181

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • openssl Arch Linux 1.0.2.i-1
  • lib32-openssl Arch Linux 1:1.0.2.i-1

arch linux advisories AVG-29AVG-30

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2016-2181 updated cvss 5.9

openssl: DTLS replay protection bypass allows DoS against DTLS connection

  • Red Hat Enterprise Linux 5 openssl Red Hat Enterprise Linux 6 openssl098e Red Hat Enterprise Linux 7 openssl098e Red Hat JBoss Enterprise Web Server 1 openssl Red Hat JBoss Enterprise Web Server 2 openssl
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux Client (v. 7) openssl 1.0.1e-51.el7_2.7, openssl-libs 1.0.1e-51.el7_2.7 Red Hat Enterprise Linux Client Optional (v. 7) openssl-perl 1.0.1e-51.el7_2.7 Red Hat Enterprise Linux ComputeNode (v. 7) openssl 1.0.1e-51.el7_2.7, openssl-libs 1.0.1e-51.el7_2.7 Red Hat Enterprise Linux ComputeNode Optional (v. 7) openssl-perl 1.0.1e-51.el7_2.7 Red Hat Enterprise Linux Desktop (v. 6) openssl 1.0.1e-48.el6_8.3 Red Hat Enterprise Linux Desktop Optional (v. 6) openssl-perl 1.0.1e-48.el6_8.3
    +10 more products
    Red Hat Enterprise Linux HPC Node (v. 6) openssl 1.0.1e-48.el6_8.3 Red Hat Enterprise Linux HPC Node Optional (v. 6) openssl-perl 1.0.1e-48.el6_8.3 Red Hat Enterprise Linux Server (v. 6) openssl 1.0.1e-48.el6_8.3 Red Hat Enterprise Linux Server (v. 7) openssl 1.0.1e-51.el7_2.7, openssl-libs 1.0.1e-51.el7_2.7 Red Hat Enterprise Linux Server Optional (v. 6) openssl-perl 1.0.1e-48.el6_8.3 Red Hat Enterprise Linux Server Optional (v. 7) openssl-perl 1.0.1e-51.el7_2.7 Red Hat Enterprise Linux Workstation (v. 6) openssl 1.0.1e-48.el6_8.3 Red Hat Enterprise Linux Workstation (v. 7) openssl 1.0.1e-51.el7_2.7, openssl-libs 1.0.1e-51.el7_2.7 Red Hat Enterprise Linux Workstation Optional (v. 6) openssl-perl 1.0.1e-48.el6_8.3 Red Hat Enterprise Linux Workstation Optional (v. 7) openssl-perl 1.0.1e-51.el7_2.7
    fixed: vendor fix RHSA-2016:1940
  • Red Hat Enterprise Linux 5 openssl097a Red Hat JBoss Core Services jbcs-httpd24-openssl Red Hat JBoss Enterprise Application Platform 6 openssl Red Hat JBoss Enterprise Web Server 3 openssl
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-22-349-21 updated cvss 7.5

Siemens SCALANCE X-200RNA Switch Devices

  • Siemens SCALANCE X204RNA (HSR) (6GK5204-0BA00-2MB2) <V3.2.7 Siemens SCALANCE X204RNA (PRP) (6GK5204-0BA00-2KB2) <V3.2.7 Siemens SCALANCE X204RNA EEC (HSR) (6GK5204-0BS00-2NA3) <V3.2.7 Siemens SCALANCE X204RNA EEC (PRP) (6GK5204-0BS00-3LA3) <V3.2.7 Siemens SCALANCE X204RNA EEC (PRP/HSR) (6GK5204-0BS00-3PA3) <V3.2.7
    affected: fixed in V3.2.7, mitigation support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

Exploit prediction

22.63% chance of exploitation in the next 30 days, higher than 97% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.