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CVE Record

CVE-2017-12237: A vulnerability in the Internet Key Exchange Version 2 (IKEv2) module of Cisco IOS 15.0 through 15.6 and Ci...

A vulnerability in the Internet Key Exchange Version 2 (IKEv2) module of Cisco IOS 15.0 through 15.6 and Cisco IOS XE 3.5 through 16.5 could allow an unauthenticated, remote attacker to cause high CPU utilization, traceback messages, or a reload of an affected device that leads to a denial of service (DoS) condition. The vulnerability is due to how an affected device processes certain IKEv2 packets. An attacker could exploit this vulnerability by sending specific IKEv2 packets to an affected device to be processed. A successful exploit could allow the attacker to cause high CPU utilization, traceback messages, or a reload of the affected device that leads to a DoS condition. This vulnerability affects Cisco devices that have the Internet Security Association and Key Management Protocol (ISAKMP) enabled. Although only IKEv2 packets can be used to trigger this vulnerability, devices that are running Cisco IOS Software or Cisco IOS XE Software are vulnerable when ISAKMP is enabled. A device does not need to be configured with any IKEv2-specific features to be vulnerable. Many features use IKEv2, including different types of VPNs such as the following: LAN-to-LAN VPN; Remote-access VPN, excluding SSL VPN; Dynamic Multipoint VPN (DMVPN); and FlexVPN. Cisco Bug IDs: CSCvc41277.

HighCVSS 7.5Known exploitedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This flaw can let an unauthenticated internet-reachable attacker disrupt affected Cisco routers or gateways by triggering high CPU use or a device reload. Business impact is availability loss, especially for VPN, WAN, or branch connectivity dependent on Cisco IOS or IOS XE devices with ISAKMP enabled.

Executive priority

Treat as high priority where affected Cisco devices support VPN or edge connectivity. KEV status means remediation should be tracked as an operational risk, not only a compliance finding.

Technical view

CVE-2017-12237 is an IKEv2 processing denial-of-service vulnerability in Cisco IOS 15.0-15.6 and IOS XE 3.5-16.5. Devices are vulnerable when ISAKMP is enabled, even without IKEv2-specific features. Successful exploitation can cause high CPU, traceback messages, or reload.

Likely exposure

Exposure is most likely on Cisco IOS or IOS XE devices using ISAKMP, including LAN-to-LAN VPN, remote-access VPN except SSL VPN, DMVPN, and FlexVPN deployments. Internet-facing VPN endpoints and edge routers deserve priority review.

Exploitation context

CISA KEV marks this CVE as known exploited. The provided sources do not describe current campaign scale, exploit availability, or specific attacker groups. The vulnerability is remotely reachable, requires no authentication, and primarily affects availability.

Researcher notes

The key exposure condition is ISAKMP enabled, not explicit IKEv2 feature configuration. Scope validation should focus on IOS and IOS XE version ranges, ISAKMP state, and externally reachable VPN/IKE surfaces.

Mitigation direction

  • Check Cisco advisory cisco-sa-20170927-ike for fixed releases and supported mitigations.
  • Prioritize remediation for internet-facing VPN and edge devices with ISAKMP enabled.
  • Review whether exposed ISAKMP/IKE services are required for each device role.
  • Use vendor-supported software trains when planning IOS or IOS XE upgrades.
  • Monitor affected devices for high CPU, tracebacks, and unexpected reloads.

Validation and detection

  • Inventory Cisco IOS and IOS XE versions across routers, gateways, and VPN endpoints.
  • Confirm whether ISAKMP is enabled on each potentially affected device.
  • Map VPN features using IKEv2-related services, including DMVPN and FlexVPN.
  • Check vulnerability records for Cisco Bug ID CSCvc41277.
  • Review device telemetry for unexplained CPU spikes, tracebacks, or reloads.
Prepared
Confidence
high
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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

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cwe · low confidence lookup

CWE-399: Exact CWE lookup

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cve · low confidence lookup

CVE-2017-12237 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
Yes
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Official CVE source material

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.

1CVSS vectors
0Timeline events
0ADP providers
3Source links

CISA KEV status

Status
Known exploited
Source
CISA / ADP
Date added
Not provided

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2017-12237Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/aCisco IOS and IOS XECisco IOS and IOS XEListed
Weakness

CWE details

CWE-399

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-399 · source CWE mapping

Resource Management Errors

Resource Management Errors represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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