# CVE-2020-3235: Cisco IOS and IOS XE Software Simple Network Management Protocol Denial of Service Vulnerability

> An authenticated remote attacker can cause a denial of service on Cisco Catalyst switches by sending crafted SNMP packets, requiring valid credentials.

- **Severity:** High 7.7 (`CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 3 Jun 2020
- **Updated:** 15 Nov 2024
- **Also known as:** GHSA-mwgg-45mm-wcjm

## What is CVE-2020-3235?

CVE-2020-3235 is a high-severity denial of service vulnerability in Cisco Ios, published on 3 Jun 2020. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS Software and Cisco IOS XE Software on Catalyst 4500 Series Switches could allow an authenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to insufficient input validation when the software processes specific SNMP object identifiers. An attacker could exploit this vulnerability by sending a crafted SNMP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Note: To exploit this vulnerability by using SNMPv2c or earlier, the attacker must know the SNMP read-only community string for an affected system. To exploit this vulnerability by using SNMPv3, the attacker must know the user credentials for the affected system.

Weakness: CWE-20 (Improper Input Validation), CWE-118 (Incorrect Access of Indexable Resource)

## Which versions are affected by CVE-2020-3235?

It affects 3 products.


Products: Cisco Ios, Cisco Ios Xe, Oracle Goldengate Management Pack.

## How do I fix CVE-2020-3235?

No fix has been published for CVE-2020-3235 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-3235 being exploited?

There is no known exploitation of CVE-2020-3235 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-2020-3235 and fix it if it is affected.

What it is: CVE-2020-3235 is a high-severity denial of service vulnerability in Cisco Ios, published on 3 Jun 2020. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-3235 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-2020-3235/ (Markdown: https://insights.sbomify.com/CVE-2020-3235/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-3235
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-3235
- OSV: https://osv.dev/vulnerability/CVE-2020-3235

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-3235/
Summaries are generated and may contain mistakes; the official description above is the record.