Cisco IOS XR Software Access Control List Bypass Vulnerability

published 2025-03-12 19 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-7290

cvss: 4.0; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 28%
public exploits: 0; none known

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

This vulnerability is due to incorrect handling of packets when a specific configuration of the hybrid ACL exists. An attacker could exploit this vulnerability by attempting to send traffic through an affected device. A successful exploit could allow the attacker to bypass a configured ACL on the affected device. For more information, see the section of this advisory. Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 19 mo ago (2025-03-21)

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 28% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	4.0	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
NVD	3.1	5.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Affected products

Cisco Cisco IOS XR Software

Classification

Weakness

CWE-284 Improper Access Control

Technology feeds

Cisco IOS rss critical rss

References

sec.cloudapps.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-ncs-hybridacl-crMZFfKQ
vendor-advisory
blog.apnic.net /2024/09/02/crafting-endless-as-paths-in-bgp/
technical-description

Sources

CVE List CVE-2025-20144
NVD CVE-2025-20144

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Summary