---
id: "CVE-2017-6627"
kind: "vulnerability"
aliases: ["CVE-2017-6627"]
title: "Cisco IOS and IOS XE Software: Cisco IOS Software and Cisco IOS XE Software UDP Packet Processing Denial-of-Service Vulnerability"
severity: "high"
cvss: 7.5
epss: 0.06158
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Cisco IOS and IOS XE Software", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["cisco", "exploited", "infrastructure", "ios", "ios-xe", "network-gear"]
not_affected_if: ["unknown"]
published_at: "2017-09-07T21:29:00+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-2017-6627", "first_seen_at": "2026-10-23T19:11:52+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2017-6627", "first_seen_at": "2026-10-23T19:13:44+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2017-6627", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

# Cisco IOS and IOS XE Software: Cisco IOS Software and Cisco IOS XE Software UDP Packet Processing Denial-of-Service Vulnerability

Cisco IOS and IOS XE have a UDP packet processing flaw that lets a remote attacker send UDP packets that wedge an interface input queue. The result is denial of service on the affected router or switch.

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

## Affected

- vendor:Cisco IOS and IOS XE Software affected ? fixed ?

## Fix

Apply the updates per the Cisco vendor advisory; the sources do not name the fixed release.

## Timeline

- 2026-10-23T19:11:52+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2017-6627
- 2026-10-23T19:13:44+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2017-6627
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2017-6627

## From the sources

A vulnerability in the UDP processing code of Cisco IOS 15.1, 15.2, and 15.4 and IOS XE 3.14 through 3.18 could allow an unauthenticated, remote attacker to cause the input queue of an affected system to hold UDP packets, causing an interface queue wedge and a denial of service (DoS) condition. The vulnerability is due to Cisco IOS Software application changes that create UDP sockets and leave the sockets idle without closing them. An attacker could exploit this vulnerability by sending UDP packets with a destination port of 0 to an affected device. A successful exploit could allow the attacker to cause UDP packets to be held in the input interfaces queue, resulting in a DoS condition. The input interface queue will stop holding UDP packets when it receives 250 packets. Cisco Bug IDs: CSCup10024, CSCva55744, CSCva95506.

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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_