PT-2025-20247 · Cisco · Cisco Ios

Published 2025-05-07 · Updated 2025-08-05 · CVE-2025-20137

Positive Technologies (AI Summary)

CVSS v3.1

4.7

Medium

Base vector

AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Name of the Vulnerable Software and Affected Versions Cisco IOS Software running on Cisco Catalyst 1000 Switches and Cisco Catalyst 2960L Switches (affected versions not specified)

Description A vulnerability in the access control list (ACL) programming could allow an unauthenticated, remote attacker to bypass a configured ACL. This issue arises when both an IPv4 ACL and a dynamic ACL of IP Source Guard are used on the same interface, which is an unsupported configuration. An attacker could exploit this by sending traffic through an affected device, potentially bypassing the ACL.

Recommendations For Cisco Catalyst 1000 Switches and Cisco Catalyst 2960L Switches, avoid configuring both IPv4 ACL and dynamic ACL of IP Source Guard on the same interface as a temporary workaround to prevent ACL bypass. At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Improper Access Control

Weakness Enumeration

CWE-284

Related Identifiers

BDU:2025-10321

CVE-2025-20137

Affected Products

Cisco Ios

References · 7

• https://nvd.nist.gov/vuln/detail/CVE-2025-20137 · Security Note
• https://osv.dev/vulnerability/CVE-2025-20137 · Vendor Advisory
• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ipsgacl-pg6qfZk · Vendor Advisory
• https://bdu.fstec.ru/vul/2025-10321 · Security Note
• https://twitter.com/CVEnew/status/1920246416951083230 · Twitter Post
• https://twitter.com/dailycve/status/1952760755456999534 · Twitter Post
• https://t.me/cveNotify/130904 · Telegram Post