dbcve.org
Ios XeOperating system · Cisco

CVE-2019-12643

CRITICAL · 10.0 CVSS v3.0 Published 2019-08-28
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable 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 the Cisco REST API virtual service container for Cisco IOS XE Software could allow an unauthenticated, remote attacker to bypass authentication on the managed Cisco IOS XE device. The vulnerability is due to an improper check performed by the area of code that manages the REST API authentication service. An attacker could exploit this vulnerability by submitting malicious HTTP requests to the targeted device. A successful exploit could allow the attacker to obtain the token-id of an authenticated user. This token-id could be used to bypass authentication and execute privileged actions through the interface of the REST API virtual service container on the affected Cisco IOS XE device. The REST API interface is not enabled by default and must be installed and activated separately on IOS XE devices. See the Details section for more information.

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

The vulnerability allows unauthenticated remote attackers to bypass authentication in the Cisco REST API virtual service container on IOS XE devices by submitting malicious HTTP requests that exploit an improper check in the authentication service code. Successful exploitation yields a valid token-id that can be used to execute privileged actions through the REST API interface.

MitigationIf the REST API is not required, leave it disabled. If needed, apply the Cisco patch/更新 for IOS XE and verify authentication behaves correctly post-update.

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:= 15.5\(3\)s3.16= 16.6.5

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/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. Verify if REST API virtual service is enabled
    Run 'show virtual-service list' or check the configuration with 'show running-config | include rest' to see if the REST API virtual service is configured and active
    Affected if REST API is enabled and running on the device
  2. Confirm the IOS XE version
    Execute 'show version' or 'show version | include IOS XE' to obtain the exact IOS XE software version number
    Affected if The installed version matches or predates the affected releases (IOS XE 15.5(3)S3 through 15.5(3)S3.16 and IOS XE 16.6.5 and earlier)
  3. Inspect REST API authentication behavior
    If REST API is enabled, review authentication logs or test unauthenticated REST API requests to verify whether the authentication check is properly enforced (do not exploit, only observe the response behavior)
    Affected if Unauthenticated HTTP requests to the REST API endpoint return valid token-ids instead of rejection

The environment is affected if the REST API virtual service is enabled and the IOS XE version falls within the affected version range, allowing authentication bypass.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

If the REST API is not required, leave it disabled. If needed, apply the Cisco patch/更新 for IOS XE and verify authentication behaves correctly post-update.

Recommended fix Moderate confidence

Cisco IOS XE 16.9.4 or later (or the latest available stable IOS XE release for your hardware platform)

  1. 1. Verify the REST API virtual service container is installed on the IOS XE device using 'show virtual-service list' or checking the configuration
  2. 2. If the REST API is not needed, ensure it remains disabled as a mitigation (it is not enabled by default)
  3. 3. If the REST API is required, upgrade the IOS XE software to a version that includes the fix for CVE-2019-12643
  4. 4. After upgrade, verify the REST API functionality works correctly with the new software version
Caveat Review Cisco release notes for any configuration or feature changes between your current version and the target upgrade version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Ios Xe Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2019-12643 in production — separate from our analysis above.

No notes yet

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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