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FedoraOperating system · Fedoraproject

CVE-2016-3071

HIGH · 7.5 CVSS v3.0 Published 2016-04-18
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
Libreswan 3.16 might allow remote attackers to cause a denial of service (daemon restart) via an IKEv2 aes_xcbc transform.

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 · moderate confidence

Libreswan 3.16 contains a vulnerability in IKEv2 handling where processing a specially crafted aes_xcbc transform causes a crash, resulting in the daemon restarting and causing denial of service. The vulnerability is remotely exploitable without authentication.

MitigationUpdate Libreswan to version 3.17 or later which contains the fix for this vulnerability. For systems that cannot be immediately updated, consider rate-limiting IKEv2 connections or implementing additional network-level controls.

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
FedoraOperating system
Affected:= 23= 24
LibreswanApplication
Affected:= 3.16

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. Determine installed Libreswan version
    Run 'ipsec --version' or 'rpm -q libreswan' to retrieve the installed version number
    Affected if The installed version is 3.16 (exact match to the affected version)
  2. Verify IKEv2 is enabled
    Examine the Libreswan configuration files for IKEv2 connection definitions (commonly in /etc/ipsec.conf or included configuration directories)
    Affected if IKEv2 connections or profiles are defined and active, as the flaw triggers during IKEv2 negotiation
  3. Check for aes_xcbc transform configuration
    Search configuration files for 'aes_xcbc' or 'xcbc' entries in the encryption or transform settings
    Affected if The aes_xcbc algorithm is configured or allowed as an accepted proposal for IKEv2 connections, which is the specific trigger for the crash

A system is affected if it runs Libreswan version 3.16 and has IKEv2 enabled with aes_xcbc transform configured or accepted, allowing a remote attacker to cause a denial of service via a specially crafted packet.

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

Update Libreswan to version 3.17 or later which contains the fix for this vulnerability. For systems that cannot be immediately updated, consider rate-limiting IKEv2 connections or implementing additional network-level controls.

Fix this in Fedora Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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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-2016-3071 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