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HighKEV

CVE-2017-12231 — Cisco IOS Software Network Address Translation Denial-of-Service Vulnerability

CVE-2017-12231 · Cisco IOS · CVSS 7.5 · KEV

In brief

Severity · CVSS
High7.5CVSS 3.1, High
EPSS
7%
CISA KEV
Known exploited, listed since 3 Mar 2022
CERT-FR
No advisory or alert referenced in the catalog
Vendor
Cisco
Published · Modified
·
Last verified

Summary

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.

Weakness: CWE-399

Title, description and the vendor's statements are quoted from the CVE record; a vendor's advisory is summarised in Patcharo's words, with a link.

Affected and fixed versions

Per product and release branch, as the vendor's CVE record and official advisory state them. A fixed release is shown only when a document names it: the vendor's, or CERT-FR's for Check Point, with its source.

Cisco IOS

Source: CVE-2017-12231cisco-sa-20170927-nat

  1. —
    Affected versionsCisco IOS
    First fixed releaseNot published in the sources followed

The vendor states fixes are available; the releases per branch are in its advisory.

Remediation

Fix available

Vendor fix

Cisco has released updates that fix this vulnerability; its advisory lists them.

SourceCisco Security Advisory cisco-sa-20170927-nat· revised 16 Dec 2022

Mitigation (vendor)

Cisco describes a workaround or a mitigation in its advisory.

SourceCisco Security Advisory cisco-sa-20170927-nat

CISA KEV required action

Apply updates per vendor instructions.

CISA due date:

SourceCISA KEV

Last verified 1 Oct 2026 at 09:31 UTC

Known exploitation

Added to CISA KEV on 3 Mar 2022

Federal remediation due date: 24 Mar 2022

The CISA required action is shown under Remediation.

7% probability of exploitation in the next 30 days (percentile 94%).

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

CERT-FR

No CERT-FR advisory or alert of the last two years references this CVE, for the vendors Patcharo covers.

Timeline

  1. Published by the source
  2. Added to CISA KEV
  3. CISA remediation due date
  4. Source record last modified
  5. EPSS score computed
  6. Last verified by Patcharo

Official sources

Vendor advisory

References

Cisco · CISA Known Exploited Vulnerabilities · NVD · FIRST EPSS · Cisco Security Advisory cisco-sa-20170927-nat

How Patcharo reads this

Affected and fixed releases come from the vendor's structured statements and are matched against exact versions; CVSS from NVD, exploitation from CISA KEV and the vendor's own advisory, probability from FIRST EPSS. Missing data stays Unknown and never becomes Not affected.

Read the methodologyRead the guide: Cisco Secure Firewall release trains: Threat Defense, Management Center and ASA versions explained