Security readout for executives and security teams
Plain-English summary
This flaw lets a remote unauthenticated attacker bypass authentication in Cisco ACI Multi-Site Orchestrator on Application Services Engine. A successful attack can issue an administrator-level token, creating a direct path to control MSO APIs and managed Cisco APIC devices.
Executive priority
Treat this as urgent for any organization using Cisco ACI MSO on Application Services Engine. The business risk is loss of administrative control over network orchestration and managed APIC infrastructure.
Technical view
CVE-2021-1388 is improper token validation on a specific MSO API endpoint. The CVSS 3.1 score is 10.0 with network attack vector, no privileges, no user interaction, scope changed, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is limited to Cisco ACI Multi-Site Orchestrator Software installed on Application Services Engine. Exact affected versions are not provided in the supplied bundle, so teams must compare deployments against Cisco’s advisory.
Exploitation context
The bundle does not show CISA KEV inclusion or other evidence of active exploitation. However, the vulnerability is remotely reachable, unauthenticated, low complexity, and can grant administrator-level API access if an affected deployment is exposed.
Researcher notes
The supplied evidence identifies the vulnerable product and impact but does not include exact versions, fixed releases, or workaround details. Avoid assuming exploitation in the wild without an additional cited source.
Mitigation direction
- Check Cisco’s advisory for affected releases and fixed software guidance.
- Prioritize upgrades or vendor-supported remediation for MSO on Application Services Engine.
- Restrict MSO API access to trusted administrative networks only.
- Review managed APIC access paths for exposure tied to MSO.
- Monitor for unexpected administrator tokens or API activity.
Validation and detection
- Inventory all Cisco ACI MSO deployments and hosting mode.
- Confirm whether each MSO instance runs on Application Services Engine.
- Map installed versions against Cisco’s advisory.
- Check whether MSO API endpoints are reachable from untrusted networks.
- Review MSO and APIC logs for unexpected admin API use.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-269: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-1388 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 10 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H3.96Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
10CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20210224 Cisco ACI Multi-Site Orchestrator Application Services Engine Deployment Authentication Bypass VulnerabilityCVE reference · vendor-advisory, x_refsource_CISCO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Privilege Management
Improper Privilege Management represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.