# CVE-2019-12652: Cisco Catalyst 4000 Series Switches TCP Denial of Service Vulnerability

> Remote attackers can cause denial of service on Cisco Catalyst 4000 switches by sending crafted TCP packets that exhaust buffer resources.

- **Severity:** High 8.6 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 25 Sep 2019
- **Updated:** 19 Nov 2024
- **Also known as:** GHSA-qr97-v3cv-xgjc

## What is CVE-2019-12652?

CVE-2019-12652 is a high-severity denial of service vulnerability in Cisco Ios, published on 25 Sep 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the ingress packet processing function of Cisco IOS Software for Cisco Catalyst 4000 Series Switches could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper resource allocation when processing TCP packets directed to the device on specific Cisco Catalyst 4000 Series Switches. An attacker could exploit this vulnerability by sending crafted TCP streams to an affected device. A successful exploit could cause the affected device to run out of buffer resources, impairing operations of control plane and management plane protocols, resulting in a DoS condition. This vulnerability can be triggered only by traffic that is destined to an affected device and cannot be exploited using traffic that transits an affected device.

Weakness: CWE-399

## Which versions are affected by CVE-2019-12652?

It affects 1 product.


Products: Cisco Ios.

## How do I fix CVE-2019-12652?

No fix has been published for CVE-2019-12652 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-12652 being exploited?

There is no known exploitation of CVE-2019-12652 in the wild and no public exploit code.

## 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-2019-12652 and fix it if it is affected.

What it is: CVE-2019-12652 is a high-severity denial of service vulnerability in Cisco Ios, published on 25 Sep 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-12652 in the wild and no public exploit code.

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-2019-12652/ (Markdown: https://insights.sbomify.com/CVE-2019-12652/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-12652
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-12652
- OSV: https://osv.dev/vulnerability/CVE-2019-12652

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From sbomify Insights: https://insights.sbomify.com/CVE-2019-12652/
Summaries are generated and may contain mistakes; the official description above is the record.