Security readout for executives and security teams
Plain-English summary
CVE-2016-5391 affects Libreswan before 3.18. A remote attacker could trigger a NULL pointer dereference that restarts the pluto daemon, disrupting IPsec VPN service. The known impact is denial of service, not data theft or code execution, based on the provided sources.
Executive priority
Treat as a service-availability risk for VPN infrastructure. Prioritize remediation where VPN downtime would interrupt operations, remote access, partner connectivity, or incident response workflows.
Technical view
The issue is a remotely triggerable crash path in Libreswan's pluto IKE daemon before version 3.18, causing daemon restart through a NULL pointer dereference. The source bundle does not provide CVSS, CWE, packet-level conditions, or broader affected-product detail beyond Libreswan before 3.18.
Likely exposure
Exposure is most relevant for systems using Libreswan for IPsec VPN termination or site-to-site tunnels, especially internet-facing or partner-facing VPN endpoints running versions before 3.18.
Exploitation context
CISA KEV is false, and the provided sources do not state active exploitation. The vulnerability is remotely reachable where Libreswan's IPsec/IKE service is exposed, but the documented outcome is service disruption through pluto restart.
Researcher notes
Available evidence is sparse: no CVSS, CWE, detailed trigger conditions, or exploit status is included. Analysis should stay anchored to the vendor-stated impact: remote denial of service via NULL pointer dereference and pluto daemon restart in Libreswan before 3.18.
Mitigation direction
- Upgrade Libreswan to version 3.18 or a vendor-supported fixed package.
- Review Fedora and distribution advisories for the exact package version to deploy.
- Prioritize exposed VPN gateways and systems supporting critical business connectivity.
- Monitor vendor guidance if legacy systems cannot be upgraded promptly.
Validation and detection
- Inventory servers running Libreswan or IPsec VPN services.
- Confirm installed Libreswan versions are 3.18 or vendor-fixed builds.
- Check whether pluto/IKE services are exposed to untrusted networks.
- Review logs for unexplained pluto daemon restarts or VPN tunnel disruption.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2016-5391 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- FEDORA-2016-d46685629dCVE reference · vendor-advisory, x_refsource_FEDORA
- FEDORA-2016-26a03340e6CVE reference · vendor-advisory, x_refsource_FEDORA
- https://bugzilla.redhat.com/show_bug.cgi?id=1356183CVE reference · x_refsource_CONFIRM
- https://libreswan.org/security/CVE-2016-5391/CVE-2016-5391.txtCVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.