ZDF
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2017-12231

Cisco IOS Software Network Address Translation Denial-of-Service Vulnerability

Published Sep 28, 2017 · catalog updated Jun 16, 2026 · Cisco IOS

Patch now

CVE-2017-12231 is in the CISA known-exploited catalog, due Mar 24, 2022. Confirm Cisco IOS against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
Severity
High7.5
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
7.07%
Remediation
Remediation guidance
Affected products
cpe cisco/ios · vendor Cisco IOS · vendor Cisco IOS software

A vulnerability in the implementation of Network Address Translation (NAT) functionality in Cisco IOS 12.4 through 15.6 could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to the improper translation of H.323 messages that use the Registration, Admission, and Status (RAS) protocol and are sent to an affected device via IPv4 packets. An attacker could exploit this vulnerability by sending a crafted H.323 RAS packet through an affected device. A successful exploit could allow the attacker to cause the affected device to crash and reload, resulting in a DoS condition. This vulnerability affects Cisco devices that are configured to use an application layer gateway with NAT (NAT ALG) for H.323 RAS messages. By default, a NAT ALG is enabled for H.323 RAS messages. Cisco Bug IDs: CSCvc57217.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe cisco/iosversion unspecified
  • vendor Cisco IOSversion unspecified
  • vendor Cisco IOS softwareversion unspecified

How to fix CVE-2017-12231

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2017-12231 is in the CISA known-exploited catalog, due Mar 24, 2022. Confirm Cisco IOS against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. Apply updates per vendor instructions.

What should an analyst verify?

CWE-399. EPSS 7.07%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Cisco security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Sep 28, 2017 · Catalog

    Detected

    A vulnerability in the implementation of Network Address Translation (NAT) functionality in Cisco IOS 12.4 through 15.6 could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to the improper translation of H.323 messages that use the Registration, Admission, and Status (RAS) protocol and are sent to an affected d

  2. Mar 3, 2022 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Mar 24, 2022 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Jun 16, 2026 · Catalog

    Updated

    A vulnerability in the implementation of Network Address Translation (NAT) functionality in Cisco IOS 12.4 through 15.6 could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to the improper translation of H.323 messages that use the Registration, Admission, and Status (RAS) protocol and are sent to an affected d

Sources

  • CISA KEVConfirmed exploitationCVE-2017-12231

    A vulnerability in the implementation of Network Address Translation (NAT) functionality in Cisco IOS could allow an unauthenticated, remote attacker to cause a denial of service.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2017-12231

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2017-12231

    30-day exploitation probability 7.1%

    first.org
  • NIST NVDVulnerability recordCVE-2017-12231

    A vulnerability in the implementation of Network Address Translation (NAT) functionality in Cisco IOS 12.4 through 15.6 could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to the improper tra

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2017-12231

    A vulnerability in the implementation of Network Address Translation (NAT) functionality in Cisco IOS could allow an unauthenticated, remote attacker to cause a denial of service.

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.