# CVE-2025-20137: Security feature bypass in IOS

> Remote attackers can bypass access control lists on Cisco Catalyst switches if IPv4 ACLs and IP Source Guard are configured together on the same interface.

- **Severity:** Medium 4.7 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 7 May 2025
- **Updated:** 7 May 2025
- **Also known as:** GHSA-x37r-wqwh-97qm

## What is CVE-2025-20137?

CVE-2025-20137 is a medium-severity vulnerability in Cisco Ios, published on 7 May 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability in the access control list (ACL) programming of Cisco IOS Software that is running on Cisco Catalyst 1000 Switches and Cisco Catalyst 2960L Switches could allow an unauthenticated, remote attacker to bypass a configured ACL.

 This vulnerability is due to the use of both an IPv4 ACL and a dynamic ACL of IP Source Guard on the same interface, which is an unsupported configuration. An attacker could exploit this vulnerability by attempting to send traffic through an affected device. A successful exploit could allow the attacker to bypass an ACL on the affected device.

 Note: Cisco documentation has been updated to reflect that this is an unsupported configuration. However, Cisco is publishing this advisory because the device will not prevent an administrator from configuring both features on the same interface. There are no plans to implement the ability to configure both features on the same interface on Cisco Catalyst 1000 or Catalyst 2960L Switches.

Weakness: CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2025-20137?

It affects 1 product.


Products: Cisco Ios.

## How do I fix CVE-2025-20137?

No fix has been published for CVE-2025-20137 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-20137 being exploited?

There is no known exploitation of CVE-2025-20137 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-2025-20137 and fix it if it is affected.

What it is: CVE-2025-20137 is a medium-severity vulnerability in Cisco Ios, published on 7 May 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-20137 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-2025-20137/ (Markdown: https://insights.sbomify.com/CVE-2025-20137/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-20137
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-20137
- OSV: https://osv.dev/vulnerability/CVE-2025-20137

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-20137/
Summaries are generated and may contain mistakes; the official description above is the record.