CVE-2021-1577 | Cisco Application Policy Infrastructure Controller Arbitrary File Read and Write 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 unauthenticated, remote attacker to read or write arbitrary files on an affected system. This vulnerability is due to improper access control. An attacker could exploit this vulnerability by using a specific API endpoint to upload a file to an affected device. A successful exploit could allow the attacker to read or write arbitrary files on an 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-2021-1577 is rated Moderate Risk (59.2/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 0.50%). 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-2021-1577

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 2026-05-09 0.73% 0.50% -0.23%
2 2025-11-21 0.51% 0.73% +0.22%
3 2025-11-18 — 0.51% —

Full EPSS history (15 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-1577

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.1 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N 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:N)
No account or special rights needed—anonymous or random user is enough.
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:N)
Service keeps running; no real outage angle.
 3.9 5.2 [email protected]
9.1 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N 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:N)
No account or special rights needed—anonymous or random user is enough.
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:N)
Service keeps running; no real outage angle.
 3.9 5.2 [email protected]
6.4 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:P/A:N 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:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 4.9 [email protected]

Weakness enumeration for CVE-2021-1577

Affected software / configurations for CVE-2021-1577

Vendor Product Version Raw CPE
cisco application_policy_infrastructure_controller < 3.2\(10e\) cpe:2.3:a:cisco:application_policy_infrastructure_controller:*:*:*:*:*:*:*:*
cisco application_policy_infrastructure_controller >= 4.0, < 4.2\(6h\) cpe:2.3:a:cisco:application_policy_infrastructure_controller:*:*:*:*:*:*:*:*
cisco application_policy_infrastructure_controller >= 5.0, < 5.1\(3e\) cpe:2.3:a:cisco:application_policy_infrastructure_controller:*:*:*:*:*:*:*:*
cisco cloud_application_policy_infrastructure_controller < 3.2\(10e\) cpe:2.3:a:cisco:cloud_application_policy_infrastructure_controller:*:*:*:*:*:*:*:*
cisco cloud_application_policy_infrastructure_controller >= 4.0, < 4.2\(6h\) cpe:2.3:a:cisco:cloud_application_policy_infrastructure_controller:*:*:*:*:*:*:*:*
cisco cloud_application_policy_infrastructure_controller >= 5.0, < 5.1\(3e\) cpe:2.3:a:cisco:cloud_application_policy_infrastructure_controller:*:*:*:*:*:*:*:*

References for CVE-2021-1577

cvelogic Threat Intelligence