How severe is CVE-2021-1577?

CVE-2021-1577 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2021-1577 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-1577?

CVE-2021-1577 primarily affects Cisco Application Policy Infrastructure Controller. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-1577?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-1577 published?

CVE-2021-1577 was published on 2021-08-25 and last updated on 2026-06-17.

CVE-2021-1577

CVE-2021-1577 is a critical-severity vulnerability in Cisco Application Policy Infrastructure Controller with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-284.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v2: 6.4
EPSS exploit prediction: 1% (67th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-284
Affected product: Cisco Application Policy Infrastructure Controller
Published: 2021-08-25
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-1577?: 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.
How severe is CVE-2021-1577?: CVE-2021-1577 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2021-1577 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-1577?: CVE-2021-1577 primarily affects Cisco Application Policy Infrastructure Controller. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-1577?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-1577 published?: CVE-2021-1577 was published on 2021-08-25 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-capic-frw-Nt3RYxR2

Affected products (2)

cpe:2.3:a:cisco:application_policy_infrastructure_controller:*:*:*:*:*:*:*:*
cpe:2.3:a:cisco:cloud_application_policy_infrastructure_controller:*:*:*:*:*:*:*:*

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