How severe is CVE-2026-20357?

CVE-2026-20357 has a CVSS 3.x base score of 10.0, 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-2026-20357 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-20357?

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-2026-20357 published?

CVE-2026-20357 was published on 2026-08-19 and last updated on 2026-08-21.

CVE-2026-20357

CVE-2026-20357 is a critical-severity vulnerability with a CVSS 3.x base score of 10.0. 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 10.0)
EPSS exploit prediction: 0% (38th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-306
Published: 2026-08-19
Last modified: 2026-08-21

Description

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Crosswork engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening release that addresses multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20357 are related to missing authentication for critical function issues that are grouped under the Common Weakness Enumeration (CWE) CWE-306.

Frequently asked questions

What is CVE-2026-20357?: As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Crosswork engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening release that addresses multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20357 are related to missing authentication for critical function issues that are grouped under the Common Weakness Enumeration (CWE) CWE-306.
How severe is CVE-2026-20357?: CVE-2026-20357 has a CVSS 3.x base score of 10.0, 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-2026-20357 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-20357?: 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-2026-20357 published?: CVE-2026-20357 was published on 2026-08-19 and last updated on 2026-08-21.

References

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

CVE-2026-58115 — Critical (CVSS 10.0): A vulnerability has been identified in SIMATIC IoT2050 Advanced (6ES7647-0BA00-1YA2) (All versions < V4.3.4.1 running…
CVE-2026-63508 — Critical (CVSS 10.0): Missing authentication for critical function in Microsoft Planetary Computer Pro allows an unauthorized attacker to…
CVE-2026-56163 — Critical (CVSS 10.0): Missing authentication for critical function in Microsoft Azure Kubernetes Service allows an unauthorized attacker to…
CVE-2026-64812 — Critical (CVSS 10.0): In JetBrains IntelliJ IDEA before 2026.2 unauthorized input injection was possible in a Remote Development session
CVE-2026-60644 — Critical (CVSS 10.0): Vulnerability in the Oracle WebCenter Content product of Oracle Fusion Middleware (component: Web Content Management).…
CVE-2026-60389 — Critical (CVSS 10.0): Vulnerability in the Service Delivery Platform product of Oracle Fusion Middleware (component: Messaging Enabler).…

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