---
id: CVE-2025-20339
title: "A vulnerability in the access control list (ACL) processing of IPv4 packets of Cisco SD-WAN vEdge Software could allow an unauthenticated, remote attacker to bypass a configured ACL.\r\n\r\nThis vulnerability is due to the improper enforceme…"
summary: "A vulnerability in the access control list (ACL) processing of IPv4 packets of Cisco SD-WAN vEdge Software could allow an unauthenticated, remote attacker to bypass a configured ACL.\r\n\r\nThis vulnerability is due to the improper enforceme…"
severity: medium
cvss: 5.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N'
cwe:
  - CWE-284
published: '2025-09-24'
updated: '2026-09-26'
sourceUpdated: '2026-09-26T00:10:00.127'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-20339'
references:
  - url: >-
      https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-defaultacl-pSJk9nVF
    label: psirt@cisco.com
tags:
  - nvd
epss: 0.00315
epssPercentile: 0.21834
ingestedAt: '2026-09-26T00:22:39.957Z'
---

## Overview

A vulnerability in the access control list (ACL) processing of IPv4 packets of Cisco SD-WAN vEdge Software could allow an unauthenticated, remote attacker to bypass a configured ACL.

This vulnerability is due to the improper enforcement of the implicit deny all at the end of a configured ACL. An attacker could exploit this vulnerability by attempting to send unauthorized traffic to an interface on an affected device. A successful exploit could allow the attacker to bypass an ACL on the affected device.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.