CVE-2017-12231

7.5 HIGH 7% exploit odds exploited in the wild Fix listed Denial of service Network gear

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of service disruption.
In the wild: CISA lists this as exploited in real attacks. Treat as urgent.
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2017-08-03 00:00 UTC ReservedThe CVE id was reserved by its CNA
2017-09-29 01:34 UTC PublishedDisclosed publicly on CVE.org and NVD
2022-03-03 Exploited in the wildAdded to CISA's Known Exploited Vulnerabilities list
2022-03-24 Remediation deadlineCISA's due date for federal agencies to fix it
2026-06-17 01:02 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: yes, CISA lists it. This puts it above everything that is not.
Exploit odds: 7.1% in the next 30 days (EPSS).
Severity: 7.5 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2017-09-29 01:34 UTC
Last modified: 2026-06-17 01:02 UTC
Added to CISA KEV: 2022-03-03
Exploit probability: 7.1% · EPSS, next 30 days
Weakness: CWE-399
Record status: Analyzed

Affected

Cisco iOS ≤ 15.6

Attack profile CVSS 3.1 · 7.5

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Raw vector

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

Is it in your code?

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Fix and advisories

References

NVD record · CVE.org record