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CVE-2016-5361· NVD / CVE Program· CNA mitre

programs/pluto/ikev1.c in libreswan before 3.17 retransmits in initial-responder states, which allows remote attackers to cause a denial of

programs/pluto/ikev1.c in libreswan before 3.17 retransmits in initial-responder states, which allows remote attackers to cause a denial of service (traffic amplification) via a spoofed UDP packet. NOTE: the original behavior complies with the IKEv1 protocol, but has a required security update from the libreswan vendor; as of 2016-06-10, it is expected that several other IKEv1 implementations will have vendor-required security updates, with separate CVE IDs assigned to each.

HighCVSS 7.5 · v3.0—No exploit Fix available
Published
Jun 16, 2016
Updated
Jun 16, 2026
EPSS
2.7% · 85th percentile
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Action score

31

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 2.7%

Affected systems

VendorProduct
libreswanlibreswan

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • libreswan libreswanup to 3.16 inclusive

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Red Hat:enterprise_linux:7::clientlibreswanbefore 0:3.15-8.el70:3.15-8.el7
Red Hat:enterprise_linux:7::clientlibreswan-debuginfobefore 0:3.15-8.el70:3.15-8.el7

Same product

libreswan: all records

Other highest-scoring records for the same primary product.

  • CVE-2013-7283Race condition in the libreswan.spec files for Red Hat Enterprise Linux (RHEL) and Fedora packages in libreswan 3.6 has unspecified impact a
    37Monitor
  • CVE-2022-23094Libreswan 4.2 through 4.5 allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted IKE
    31Monitor
  • CVE-2020-1763An out-of-bounds buffer read flaw was found in the pluto daemon of libreswan from versions 3.27 till 3.31 where, an unauthenticated attacker
    31Monitor
  • CVE-2019-12312In Libreswan 3.27 an assertion failure can lead to a pluto IKE daemon restart.
    31Monitor
  • CVE-2016-5391libreswan before 3.18 allows remote attackers to cause a denial of service (NULL pointer dereference and pluto daemon restart).
    31Monitor
  • CVE-2016-3071Libreswan 3.16 might allow remote attackers to cause a denial of service (daemon restart) via an IKEv2 aes_xcbc transform.
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
red hat:libreswan0:3.15-8.el7 · Red Hat:enterprise_linux:7::clientPackage registry (OSV)
red hat:libreswan-debuginfo0:3.15-8.el7 · Red Hat:enterprise_linux:7::clientPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-20 · Improper Input Validation

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Noroxi analysis

No Noroxi analysis for this record yet

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Change log

  1. Fix✗ → ✓

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References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records