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OpenSSLFramework / library

CVE-2016-2179

HIGH · 7.5 CVSS v3.0 Published 2016-09-16
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The DTLS implementation in OpenSSL before 1.1.0 does not properly restrict the lifetime of queue entries associated with unused out-of-order messages, which allows remote attackers to cause a denial of service (memory consumption) by maintaining many crafted DTLS sessions simultaneously, related to d1_lib.c, statem_dtls.c, statem_lib.c, and statem_srvr.c.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Memory exhaustion DoS vulnerability in OpenSSL's DTLS implementation prior to 1.1.0. The DTLS state machine fails to properly restrict or expire queue entries associated with unused out-of-order messages, allowing remote attackers to exhaust server memory by maintaining many crafted DTLS sessions simultaneously.

MitigationUpgrade OpenSSL to version 1.1.0 or later. If DTLS cannot be upgraded, consider disabling DTLS or implementing connection rate limiting and session limits at the network perimeter.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
OpenSSLFramework / library
Affected:= 1.0.1= 1.0.1a= 1.0.1b= 1.0.1c= 1.0.1d= 1.0.1e= 1.0.1f= 1.0.1g= 1.0.1h= 1.0.1i= 1.0.1j= 1.0.1k
LinuxOperating system
Affected:= 6= 7

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed OpenSSL version
    Run 'openssl version' to see the installed version, or check the OpenSSL library file directly with 'openssl version -a'
    Affected if Version starts with 1.0.1 and matches any of the affected patch levels (a through k), or falls within the 1.0.1x range prior to 1.0.2
  2. Determine if DTLS is enabled
    Check configuration files and running services for DTLS usage - look for 'DTLS' in application configs, or check listening services with 'ss -ulnp' or 'netstat -ulnp' for DTLS ports (typically 443/udp for DTLS, or custom UDP ports)
    Affected if DTLS is actively configured or running on the system
  3. Check for DTLS client hello or handshake activity
    Monitor UDP traffic on common DTLS ports or examine application logs for DTLS handshake messages using packet capture (tcpdump) or SSL logs
    Affected if DTLS connections are being accepted or processed by the system
  4. Verify Oracle Linux DTLS packages
    If the system is Oracle Linux, check installed packages with 'rpm -qa | grep -i openssl' to see if OpenSSL from Oracle Linux repositories is installed
    Affected if OpenSSL packages from Oracle Linux 6 or 7 are installed with vulnerable versions

The system is affected if it runs any OpenSSL 1.0.1.x version (a through k) with DTLS enabled and processing incoming DTLS connections, allowing remote attackers to exhaust memory via crafted DTLS sessions.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade OpenSSL to version 1.1.0 or later. If DTLS cannot be upgraded, consider disabling DTLS or implementing connection rate limiting and session limits at the network perimeter.

Fix this in OpenSSL Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2016-2179 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data