# CVE-2017-6627: Cisco IOS Software and Cisco IOS XE Software UDP Packet Processing Denial-of-Service

> Remote attackers can cause a denial of service on Cisco IOS devices by sending UDP packets to port 0, wedging the interface queue.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Yes, since 3 Mar 2022 (CISA KEV)
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 7 Sep 2017
- **Updated:** 21 Oct 2025
- **Also known as:** GHSA-c93x-vxh6-pfqp

## What is CVE-2017-6627?

CVE-2017-6627 is a high-severity denial of service vulnerability in Cisco Ios, published on 7 Sep 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-404 (Improper Resource Shutdown or Release), CWE-399

## Which versions are affected by CVE-2017-6627?

It affects 2 products.


Products: Cisco Ios, Cisco Ios Xe.

## How do I fix CVE-2017-6627?

No fix has been published for CVE-2017-6627 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 24 Mar 2022.

## Is CVE-2017-6627 being exploited?

Yes. Attackers have exploited CVE-2017-6627 in the wild since at least 3 Mar 2022.

## Other vulnerabilities in Cisco Ios

- [CVE-2017-12240](https://insights.sbomify.com/CVE-2017-12240/): Cisco IOS and IOS XE Software DHCP Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2017-3881](https://insights.sbomify.com/CVE-2017-3881/): Cisco IOS and IOS XE Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2018-0167](https://insights.sbomify.com/CVE-2018-0167/): Cisco IOS, XR, and XE Software Buffer Overflow (high 8.8, exploited in the wild)
- [CVE-2017-6736](https://insights.sbomify.com/CVE-2017-6736/): Cisco IOS and IOS XE Software SNMP Remote Code Execution (high 8.8, exploited in the wild)
- [CVE-2017-6737](https://insights.sbomify.com/CVE-2017-6737/): Cisco IOS and IOS XE Software SNMP Remote Code Execution (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-6627 and fix it if it is affected.

What it is: CVE-2017-6627 is a high-severity denial of service vulnerability in Cisco Ios, published on 7 Sep 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2017-6627 in the wild since at least 3 Mar 2022.

Affected product: Cisco Ios. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2017-6627/ (Markdown: https://insights.sbomify.com/CVE-2017-6627/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-6627
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-6627
- OSV: https://osv.dev/vulnerability/CVE-2017-6627

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From sbomify Insights: https://insights.sbomify.com/CVE-2017-6627/
Summaries are generated and may contain mistakes; the official description above is the record.