---
id: "CVE-2017-12232"
kind: "vulnerability"
aliases: ["CVE-2017-12232"]
title: "Cisco IOS software: Cisco IOS Software for Cisco Integrated Services Routers Denial-of-Service Vulnerability"
severity: "high"
cvss: 6.5
epss: 0.02153
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Cisco IOS software", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["cisco", "exploited", "infrastructure", "ios", "isr-g2", "network-appliance"]
not_affected_if: ["no-affected-protocol-enabled", "not-isr-g2"]
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-2017-12232", "first_seen_at": "2026-10-23T19:11:52+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2017-12232", "first_seen_at": "2026-10-23T19:13:44+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2017-12232", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

# Cisco IOS software: Cisco IOS Software for Cisco Integrated Services Routers Denial-of-Service Vulnerability

A protocol implementation flaw in Cisco IOS on Integrated Services Routers Generation 2 lets an unauthenticated attacker on the adjacent network cause the device to reload. The result is a denial of service, and CISA lists it as known exploited.

_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 specific fixed IOS version is not stated in the sources.

## Timeline

- 2026-10-23T19:11:52+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2017-12232
- 2026-10-23T19:13:44+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2017-12232
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2017-12232

## From the sources

A vulnerability in the implementation of a protocol in Cisco Integrated Services Routers Generation 2 (ISR G2) Routers running Cisco IOS 15.0 through 15.6 could allow an unauthenticated, adjacent attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to a misclassification of Ethernet frames. An attacker could exploit this vulnerability by sending a crafted Ethernet frame to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCvc03809.

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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_