CVE-2021-1578 | Cisco Application Policy Infrastructure Controller Privilege Escalation Vulnerability

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 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.

Published: 2021-08-25 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-1578 is rated Moderate Risk (63/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.91%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-1578

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 1.05% 1.91% +0.86%
2 2026-01-25 0.67% 1.05% +0.37%
3 2025-11-21 — 0.67% —

Full EPSS history (14 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-1578

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
9.0 2.0 HIGH
AV:N/AC:L/Au:S/C:C/I:C/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
 8.0 10.0 [email protected]

Weakness enumeration for CVE-2021-1578

Affected software / configurations for CVE-2021-1578

Vendor Product Version Raw CPE
cisco application_policy_infrastructure_controller >= 5.0, <= 5.1\(3e\) cpe:2.3:a:cisco:application_policy_infrastructure_controller:*:*:*:*:*:*:*:*
cisco application_policy_infrastructure_controller 5.0\(2h\) cpe:2.3:a:cisco:application_policy_infrastructure_controller:5.0\(2h\):*:*:*:*:*:*:*
cisco cloud_application_policy_infrastructure_controller >= 5.0, <= 5.1\(3e\) cpe:2.3:a:cisco:cloud_application_policy_infrastructure_controller:*:*:*:*:*:*:*:*
cisco cloud_application_policy_infrastructure_controller 5.0\(2h\) cpe:2.3:a:cisco:cloud_application_policy_infrastructure_controller:5.0\(2h\):*:*:*:*:*:*:*

References for CVE-2021-1578

cvelogic Threat Intelligence