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iOSOperating system · Cisco

CVE-2025-20181

MEDIUM · 6.8 CVSS v3.0 Published 2025-05-07
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
73/100
Remediation priority · Elevated
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability in Cisco IOS Software for Cisco Catalyst 2960X, 2960XR, 2960CX, and 3560CX Series Switches could allow an authenticated, local attacker with privilege level 15 or an unauthenticated attacker with physical access to the device to execute persistent code at boot time and break the chain of trust. This vulnerability is due to missing signature verification for specific files that may be loaded during the device boot process. An attacker could exploit this vulnerability by placing a crafted file into a specific location on an affected device. A successful exploit could allow the attacker to execute arbitrary code at boot time. Because this allows the attacker to bypass a major security feature of the device, Cisco has raised the Security Impact Rating (SIR) of this advisory from Medium to High.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

This vulnerability in Cisco IOS Software for Catalyst 2960X, 2960XR, 2960CX, and 3560CX switches allows attackers to bypass signature verification for files loaded during boot. An authenticated privilege-15 user or someone with physical access can place a crafted file in a specific location to execute arbitrary code at boot time, breaking the chain of trust.

MitigationApply the Cisco-provided firmware update that implements signature verification for boot-time files. For devices that cannot be immediately patched, restrict physical access and limit privilege-15 accounts.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
iOSOperating system
Affected:= 15.0\(1\)ex= 15.0\(1\)ey= 15.0\(1\)ey1= 15.0\(1\)ey2= 15.0\(1\)xo= 15.0\(1\)xo1= 15.0\(2\)ex= 15.0\(2\)ex1= 15.0\(2\)ex2= 15.0\(2\)ex3= 15.0\(2\)ex4= 15.0\(2\)ex5

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Physical
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the installed IOS version
    Run the command 'show version' on the switch CLI and locate the 'IOS' or 'IOS-XE' version string in the output
    Affected if The version displayed matches one of these: 15.0(1)ex, 15.0(1)ey, 15.0(1)ey1, 15.0(1)ey2, 15.0(1)xo, 15.0(1)xo1, 15.0(2)ex, 15.0(2)ex1, 15.0(2)ex2, 15.0(2)ex3, 15.0(2)ex4, 15.0(2)ex5
  2. Confirm the switch model is affected
    Run 'show version' and verify the model name is Catalyst 2960X, 2960XR, 2960CX, or 3560CX
    Affected if The device model is any of these four switch series and the version matches step 1
  3. Check the current boot configuration
    Run 'show boot' or 'show running-config | include boot' to view boot system settings and file locations configured on the device
    Affected if Non-default boot files or configurations are present that could indicate tampering or custom loading paths
  4. Verify secure boot status if available
    Run 'show secure-boot' or check for 'secure boot' related commands in 'show version' output
    Affected if Secure boot verification is disabled, not configured, or shows a status indicating the chain of trust is not enforced

The device is affected if it is a Catalyst 2960X, 2960XR, 2960CX, or 3560CX switch running any of the listed IOS versions and the secure boot mechanism is not properly enforcing signature verification for boot files.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Cisco-provided firmware update that implements signature verification for boot-time files. For devices that cannot be immediately patched, restrict physical access and limit privilege-15 accounts.

Fix this in iOS Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-20181 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
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