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Vulnerability Intelligence

CVE-2017-12237

HighExploitedPublic exploit

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…

Published Sep 28, 2017 · Updated Apr 21, 2026

Key Facts

Patch immediately
  • CVE-2017-12237 is a high-severity vulnerability (CVSS 7.5 v3.1) affecting IOS (Cisco), IOS Xe (Cisco), Cisco IOS and IOS XE.
  • It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Mar 3, 2022. Public exploit code is available.
  • EPSS estimates a 7.1% probability of exploitation in the next 30 days.
  • Fixed versions are available, including IOS 15.6, IOS Xe 16.5.
  • Brandefense priority: patch immediately, because it is listed as exploited in the wild.

CVSS v3.1

7.5

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

EPSS (30-day exploit likelihood)

7.1%

Higher than 94.1% of all scored CVEs

Exploited in the wild

Yes

4 catalog listings

Public exploit code

Available

Proof-of-concept or weaponized module

Get the full CVE-2017-12237 brief as a PDF

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Description

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.

Known-Exploited Catalog Listings

CatalogAddedRemediation dueRansomware use
CISA KEVMar 3, 2022Mar 24, 2022Not reported
Industry KEV feedMar 3, 2022Mar 24, 2022Not reported
CIRCL KEVMar 3, 2022Mar 24, 2022Not reported
ENISA EUVDMar 3, 2022n/aNot reported

Required action: Apply updates per vendor instructions.

Affected Products

3 affected entries in total
ProductAffected versionsFixed in
IOSCiscoSee advisory15.6
IOS XeCiscoSee advisory16.5
Cisco IOS and IOS XE>= Cisco IOS and IOS XEn/a

Patched Releases

IOS

15.6

IOS Xe

16.5

Timeline

  1. Publicly disclosed

    Sep 28, 2017

  2. Added to CISA KEV

    Mar 3, 2022

  3. Added to Industry KEV feed

    Mar 3, 2022

  4. Added to CIRCL KEV

    Mar 3, 2022

  5. Added to ENISA EUVD

    Mar 3, 2022

  6. Last updated

    Apr 21, 2026

Weakness Type

  • CWE-399

References

1 more references in the full CVE brief

FAQ

Common Questions.

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