CVE-2017-12231

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

  • High 7.5
  • Exploited: added to CISA KEV 3 Mar 2022

Description

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.

Key facts

Published
28 Sep 2017
Last changed
14 Jan 2026
Assigned by
cisco
KEV added
3 Mar 2022
KEV fix due
24 Mar 2022
EPSS
7.07% likely to be exploited in the next 30 days, higher than 94.311% of CVEs (scores for 15 Nov 2026)
SSVC (CISA)
Exploitation: active; Automatable: yes; Technical impact: partial

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

  • 7.5CVSS 3.1, Highfrom CISA (ADP container)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

What to do

  • Apply updates per vendor instructions.CISA KEV required action

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

VendorProductVersions
n/aCisco IOS
  • Cisco IOS (affected)

Timeline

  1. 28 Sep 2017 Published
  2. 3 Mar 2022 Added to the CISA KEV catalogue

Weakness

References