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Aci Multi Site OrchestratorApplication · Cisco

CVE-2021-1388

CRITICAL · 10.0 CVSS v3.1 Published 2021-02-24
Fix available
A fix is available. Upgrade to 3.0 or later.
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 an API endpoint of Cisco ACI Multi-Site Orchestrator (MSO) installed on the Application Services Engine could allow an unauthenticated, remote attacker to bypass authentication on an affected device. The vulnerability is due to improper token validation on a specific API endpoint. An attacker could exploit this vulnerability by sending a crafted request to the affected API. A successful exploit could allow the attacker to receive a token with administrator-level privileges that could be used to authenticate to the API on affected MSO and managed Cisco Application Policy Infrastructure Controller (APIC) devices.

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 · moderate confidence

Cisco ACI Multi-Site Orchestrator contains an authentication bypass vulnerability in a specific API endpoint due to improper token validation. An unauthenticated remote attacker can send a crafted request to receive a valid administrator-level token, enabling authentication to the MSO API and managed APIC devices.

MitigationApply the vendor patch from Cisco for this vulnerability. As an immediate safeguard, restrict network access to the MSO API endpoints to trusted management networks until the patch can be deployed.

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
Aci Multi Site OrchestratorApplication
Affected:>= 3.0, < 3.0\(3m\)
Application Policy Infrastructure ControllerApplication
Affected:= 3.0\(3i\)

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:3.1/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. Identify installed Cisco ACI products
    Inventory your environment for installations of Cisco ACI Multi-Site Orchestrator (MSO) or Cisco Application Policy Infrastructure Controller (APIC)
    Affected if Either product is present in the environment
  2. Determine MSO version
    Use the MSO administrative interface or run 'show version' via CLI to retrieve the installed version number
    Affected if Version is 3.0 or higher but lower than 3.0(3m)
  3. Determine APIC version
    Use the APIC administrative interface or run 'show version' via CLI to retrieve the installed version number
    Affected if APIC version is exactly 3.0(3i)
  4. Verify API network exposure
    Review firewall rules, ACLs, or network segmentation to determine if the MSO API endpoint (port 443/https) is reachable from untrusted networks
    Affected if The MSO API is accessible from untrusted or public networks

Your environment is affected if you run Cisco ACI Multi-Site Orchestrator version 3.0 through 3.0(3m)-1 or APIC version 3.0(3i), and the MSO API endpoint is network-accessible to untrusted parties.

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
Upgrade available Upgrade to 3.0 or later
Fixed in 3.0
Interim mitigation

Apply the vendor patch from Cisco for this vulnerability. As an immediate safeguard, restrict network access to the MSO API endpoints to trusted management networks until the patch can be deployed.

Recommended fix Moderate confidence

Cisco ACI MSO: upgrade to 3.0(3m) or later; Cisco APIC: upgrade to the fixed release as specified in Cisco advisory

  1. Identify current installed version of Cisco ACI Multi-Site Orchestrator (MSO) and Application Policy Infrastructure Controller (APIC)
  2. For MSO: Upgrade to version 3.0(3m) or later to remediate the authentication bypass vulnerability
  3. For APIC: Apply the corresponding fixed release as indicated in Cisco's official advisory for this CVE
  4. After upgrade, verify that the API authentication now properly validates tokens
  5. Confirm that the upgraded version is not listed as affected in the CVE
Caveat Review Cisco release notes for upgrade considerations and potential configuration or compatibility impacts before proceeding

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

Fix this in Aci Multi Site Orchestrator Scoped from the published advisory
  • Consultation8.0 h
  • Implementation6.0 h
  • Testing16.0 h
  • Review / QA4.0 h
34.0 hours of engineering $5,800
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $9,280.

Scan for this in your stack

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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-2021-1388 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