Cyber Resilience

CVE-2021-1578

High

Published: 25 August 2021

Published
25 August 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0105 77.9th percentile
Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-1578 is a high-severity Failing Open (CWE-636) vulnerability in Cisco Application Policy Infrastructure Controller. Its CVSS base score is 8.8 (High).

Operationally, ranked in the top 22.1% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

A vulnerability in an API endpoint of Cisco Application Policy Infrastructure Controller (APIC) and Cisco Cloud Application Policy Infrastructure Controller (Cloud APIC) could allow an authenticated, remote attacker to elevate privileges to Administrator on an affected device. This vulnerability is…

more

due to an improper policy default setting. An attacker could exploit this vulnerability by using a non-privileged credential for Cisco ACI Multi-Site Orchestrator (MSO) to send a specific API request to a managed Cisco APIC or Cloud APIC device. A successful exploit could allow the attacker to obtain Administrator credentials on the affected device.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

cisco
application policy infrastructure controller
5.0\(2h\) · 5.0 — 5.1\(3e\)
cisco
cloud application policy infrastructure controller
5.0\(2h\) · 5.0 — 5.1\(3e\)

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-636 CWE-755

Supports failing securely by requiring alerts and configurable actions (e.g., shutdown) when the audit mechanism fails instead of continuing without it.

addresses: CWE-636 CWE-755

Entering safe mode when conditions are detected prevents failing open and continuing normal operation in a potentially exploitable state.

addresses: CWE-636 CWE-755

Directly requires transition to a known (secure) state on failure, preventing fail-open behavior.

addresses: CWE-636 CWE-755

Standby components and explicit exchange criteria enforce a controlled, secure failover instead of failing open.

addresses: CWE-636 CWE-755

Directly implements fail-safe (fail-closed/secure) behavior on indicated failures, preventing the system from defaulting to an insecure open state.

addresses: CWE-636

Ensures audit logging continues on primary failure instead of failing open with no logging capability.

addresses: CWE-636

Ensures security functions remain enforced via alternatives instead of defaulting to an insecure state when the primary means fails.

addresses: CWE-755

By preparing users for contingency scenarios, the control promotes proper handling of exceptional conditions instead of default or unsafe behaviors.

References