How severe is CVE-2021-1393?

CVE-2021-1393 has a CVSS 3.x base score of 9.8, 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 high.

Is CVE-2021-1393 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-1393?

CVE-2021-1393 primarily affects Cisco Application Services Engine. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-1393?

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-2021-1393 published?

CVE-2021-1393 was published on 2021-02-24 and last updated on 2026-06-17.

CVE-2021-1393

CVE-2021-1393 is a critical-severity vulnerability in Cisco Application Services Engine with a CVSS 3.x base score of 9.8. 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-306.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 10.0
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-306
Affected product: Cisco Application Services Engine
Published: 2021-02-24
Last modified: 2026-06-17

Description

Multiple vulnerabilities in Cisco Application Services Engine could allow an unauthenticated, remote attacker to gain privileged access to host-level operations or to learn device-specific information, create diagnostic files, and make limited configuration changes. For more information about these vulnerabilities, see the Details section of this advisory.

Frequently asked questions

What is CVE-2021-1393?: Multiple vulnerabilities in Cisco Application Services Engine could allow an unauthenticated, remote attacker to gain privileged access to host-level operations or to learn device-specific information, create diagnostic files, and make limited configuration changes. For more information about these vulnerabilities, see the Details section of this advisory.
How severe is CVE-2021-1393?: CVE-2021-1393 has a CVSS 3.x base score of 9.8, 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 high.
Is CVE-2021-1393 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-1393?: CVE-2021-1393 primarily affects Cisco Application Services Engine. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-1393?: 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-2021-1393 published?: CVE-2021-1393 was published on 2021-02-24 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-case-mvuln-dYrDPC6w

Affected products (3)

cpe:2.3:a:cisco:application_services_engine:*:*:*:*:*:*:*:*
cpe:2.3:a:cisco:application_policy_infrastructure_controller:1.1.3:c:*:*:*:*:*:*
cpe:2.3:a:cisco:application_policy_infrastructure_controller:1.1.3:d:*:*:*:*:*:*

More vulnerabilities in Cisco Application Services Engine

CVE-2021-1396 — Critical (CVSS 9.8): Multiple vulnerabilities in Cisco Application Services Engine could allow an unauthenticated, remote attacker to gain…
CVE-2020-3335 — Medium (CVSS 5.5): A vulnerability in the key store of Cisco Application Services Engine Software could allow an authenticated, local…
CVE-2020-3333 — Medium (CVSS 5.3): A vulnerability in the API of Cisco Application Services Engine Software could allow an unauthenticated, remote…

All CVEs affecting Cisco Application Services Engine →

Other CWE-306 (Missing Authentication for Critical Function) vulnerabilities

CVE-2026-54309 — Critical (CVSS 10.0): n8n is an open source workflow automation platform. Prior to 2.25.7 and 2.26.2, when @n8n/mcp-browser is run in HTTP…
CVE-2026-50242 — Critical (CVSS 10.0): In JetBrains Hub before 2026.1.13757, 2025.3.148033, 2025.2.148048, 2025.1.148120, 2024.3.148430, 2024.2.148429…
CVE-2026-49257 — Critical (CVSS 10.0): mcp-pinot is a Python-based Model Context Protocol (MCP) server for interacting with Apache Pinot. In versions 3.0.1…
CVE-2026-46846 — Critical (CVSS 10.0): Vulnerability in the Oracle WebCenter Portal product of Oracle Fusion Middleware (component: Security Framework).…
CVE-2026-46803 — Critical (CVSS 10.0): Vulnerability in the Oracle WebCenter Portal product of Oracle Fusion Middleware (component: Security Framework).…
CVE-2026-46800 — Critical (CVSS 10.0): Vulnerability in the Oracle WebCenter Sites product of Oracle Fusion Middleware (component: WebCenter Sites).…

Browse all CWE-306 (Missing Authentication for Critical Function) vulnerabilities →