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Ios XeOperating system · Cisco

CVE-2019-12649

MEDIUM · 6.7 CVSS v3.1 Published 2019-09-25
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
69/100
Remediation priority · Elevated
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 the Image Verification feature of Cisco IOS XE Software could allow an authenticated, local attacker to install and boot a malicious software image or execute unsigned binaries on an affected device. The vulnerability exists because, under certain circumstances, an affected device can be configured to not verify the digital signatures of system image files during the boot process. An attacker could exploit this vulnerability by abusing a specific feature that is part of the device boot process. A successful exploit could allow the attacker to install and boot a malicious software image or execute unsigned binaries on the targeted device.

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

A vulnerability in Cisco IOS XE's Image Verification feature allows an authenticated local attacker to bypass digital signature checks during the boot process, enabling installation of malicious software images or execution of unsigned binaries. The flaw occurs when certain configurations permit skipping signature verification of system image files.

MitigationEnsure image verification/signatures are always enforced in the device configuration, disable any feature allowing verification bypass, and update to a patched Cisco IOS XE version.

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
Ios XeOperating system
Affected:= 16.8\(1\)
iOSOperating system
Affected:= 16.9.1

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
Local
Complexity
Low
Privileges
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:H/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. Check the device IOS/XE version
    Run 'show version' and look at the version string (e.g., Cisco IOS XE Software, Version 16.8.1 or Cisco IOS Software, Version 16.9.1)
    Affected if The version matches 16.8.1 for IOS XE or 16.9.1 for iOS (exact version match to affected releases)
  2. Verify if Image Verification is configured
    Run 'show running-config | include image' or 'show running-config all' and look for image verification related commands such as 'image verification' or 'no image verification'
    Affected if Image verification is explicitly configured (the presence of any image verification commands indicates the feature is being used)
  3. Check for verification bypass settings
    Run 'show running-config' and search for commands that disable signature verification, such as 'no verify' or 'no signature verification' options under the image or boot configuration
    Affected if Any configuration exists that disables or bypasses image signature verification (e.g., 'no verify' commands)
  4. Inspect boot system configuration
    Run 'show boot system' or 'show running-config | include boot' to examine how the device is configured to boot and load system images
    Affected if The boot configuration includes settings that could skip integrity checks on loaded images

A device is affected if it runs exactly version 16.8.1 (IOS XE) or 16.9.1 (iOS) AND has image verification configured with bypass-enabled settings present in the configuration.

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

Ensure image verification/signatures are always enforced in the device configuration, disable any feature allowing verification bypass, and update to a patched Cisco IOS XE version.

Fix this in Ios Xe Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,330
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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-2019-12649 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
  • No spam, self-promotion, credentials, or personal data