# CVE-2025-20316: Security feature bypass in Cisco IOS XE Software

> An unauthenticated remote attacker can bypass egress ACLs on Cisco Catalyst switches by flooding traffic to flush the MAC address table.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Sep 2025
- **Updated:** 24 Sep 2025
- **Also known as:** GHSA-84gm-4jph-65cm

## What is CVE-2025-20316?

CVE-2025-20316 is a medium-severity vulnerability in Cisco IOS XE Software, published on 24 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the access control list (ACL) programming of Cisco IOS XE Software for Cisco Catalyst 9500X and 9600X Series Switches could allow an unauthenticated, remote attacker to bypass a configured ACL on an affected device.

 This vulnerability is due to the flooding of traffic from an unlearned MAC address on a switch virtual interface (SVI) that has an egress ACL applied. An attacker could exploit this vulnerability by causing the VLAN to flush its MAC address table. This condition can also occur if the MAC address table is full. A successful exploit could allow the attacker to bypass an egress ACL on an affected device.

Weakness: CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2025-20316?


## How do I fix CVE-2025-20316?

No fix has been published for CVE-2025-20316 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-20316 being exploited?

There is no known exploitation of CVE-2025-20316 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-20316 and fix it if it is affected.

What it is: CVE-2025-20316 is a medium-severity vulnerability in Cisco IOS XE Software, published on 24 Sep 2025. 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-2025-20316 in the wild and no public exploit code.

Affected product: Cisco IOS XE Software. 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-2025-20316/ (Markdown: https://insights.sbomify.com/CVE-2025-20316/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-20316
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-20316
- OSV: https://osv.dev/vulnerability/CVE-2025-20316

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-20316/
Summaries are generated and may contain mistakes; the official description above is the record.