---
id: "CVE-2017-12235"
kind: "vulnerability"
aliases: ["CVE-2017-12235"]
title: "Cisco IOS software: Cisco IOS Software for Cisco Industrial Ethernet Switches PROFINET Denial-of-Service Vulnerability"
severity: "high"
cvss: 7.8
epss: 0.0707
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Cisco IOS software", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["cisco", "exploited", "industrial-ethernet", "infrastructure", "ios", "profinet"]
not_affected_if: ["no-profinet-enabled", "not-industrial-ethernet-switch"]
published_at: "2017-09-29T01:34:48+00:00"
first_seen_at: "2026-10-23T19:11:52+00:00"
updated_at: "2026-10-23T21:57:35+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2017-12235", "first_seen_at": "2026-10-23T19:11:52+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2017-12235", "first_seen_at": "2026-10-23T19:13:44+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2017-12235", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

# Cisco IOS software: Cisco IOS Software for Cisco Industrial Ethernet Switches PROFINET Denial-of-Service Vulnerability

Cisco IOS software on Cisco Industrial Ethernet switches mishandles PROFINET Discovery and Configuration Protocol (PN-DCP) packets. An unauthenticated remote attacker can make the device reload, causing a denial of service.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Cisco IOS software affected ? fixed ?

## Fix

Apply the updates per Cisco's vendor instructions; the sources do not name a fixed version.

## Timeline

- 2026-10-23T19:11:52+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2017-12235
- 2026-10-23T19:13:44+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2017-12235
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2017-12235

## From the sources

A vulnerability in the implementation of the PROFINET Discovery and Configuration Protocol (PN-DCP) for Cisco IOS 12.2 through 15.6 could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to the improper parsing of ingress PN-DCP Identify Request packets destined to an affected device. An attacker could exploit this vulnerability by sending a crafted PN-DCP Identify Request packet to an affected device and then continuing to send normal PN-DCP Identify Request packets to the device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. This vulnerability affects Cisco devices that are configured to process PROFINET messages. Beginning with Cisco IOS Software Release 12.2(52)SE, PROFINET is enabled by default on all the base switch module and expansion-unit Ethernet ports. Cisco Bug IDs: CSCuz47179.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_