How severe is CVE-2020-3257?

CVE-2020-3257 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2020-3257 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-3257?

CVE-2020-3257 primarily affects Cisco Ios. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-3257?

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

When was CVE-2020-3257 published?

CVE-2020-3257 was published on 2020-06-03 and last updated on 2026-06-17.

CVE-2020-3257

CVE-2020-3257 is a high-severity vulnerability in Cisco Ios with a CVSS 3.x base score of 8.1. 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-119.

Key facts

Severity: High (CVSS 3.x base score 8.1)
CVSS v2: 4.8
EPSS exploit prediction: 1% (49th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-119
Affected product: Cisco Ios
Published: 2020-06-03
Last modified: 2026-06-17

Description

Multiple vulnerabilities in the Cisco IOx application environment of Cisco 809 and 829 Industrial Integrated Services Routers (Industrial ISRs) and Cisco 1000 Series Connected Grid Routers (CGR1000) that are running Cisco IOS Software could allow an attacker to cause a denial of service (DoS) condition or execute arbitrary code with elevated privileges on an affected device. For more information about these vulnerabilities, see the Details section of this advisory.

Frequently asked questions

What is CVE-2020-3257?: Multiple vulnerabilities in the Cisco IOx application environment of Cisco 809 and 829 Industrial Integrated Services Routers (Industrial ISRs) and Cisco 1000 Series Connected Grid Routers (CGR1000) that are running Cisco IOS Software could allow an attacker to cause a denial of service (DoS) condition or execute arbitrary code with elevated privileges on an affected device. For more information about these vulnerabilities, see the Details section of this advisory.
How severe is CVE-2020-3257?: CVE-2020-3257 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2020-3257 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-3257?: CVE-2020-3257 primarily affects Cisco Ios. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-3257?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-3257 published?: CVE-2020-3257 was published on 2020-06-03 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ios-iot-gos-vuln-s9qS8kYL

Affected products (2)

cpe:2.3:o:cisco:ios:15.8\(3.0z\)m1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:15.9:*:*:*:*:*:*:*

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