How severe is CVE-2020-3500?

CVE-2020-3500 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2020-3500 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-3500?

CVE-2020-3500 affects Cisco Staros. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-3500?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-3500 published?

CVE-2020-3500 was published on 2020-08-17 and last updated on 2026-06-17.

CVE-2020-3500

CVE-2020-3500 is a medium-severity vulnerability in Cisco Staros with a CVSS 3.x base score of 6.8. 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-119.

Key facts

Severity: Medium (CVSS 3.x base score 6.8)
CVSS v2: 7.8
EPSS exploit prediction: 2% (73rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-119
Affected product: Cisco Staros
Published: 2020-08-17
Last modified: 2026-06-17

Description

A vulnerability in the IPv6 implementation of Cisco StarOS could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient validation of incoming IPv6 traffic. An attacker could exploit this vulnerability by sending a crafted IPv6 packet to an affected device with the goal of reaching the vulnerable section of the input buffer. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition. This vulnerability is specific to IPv6 traffic. IPv4 traffic is not affected.

Frequently asked questions

What is CVE-2020-3500?: A vulnerability in the IPv6 implementation of Cisco StarOS could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient validation of incoming IPv6 traffic. An attacker could exploit this vulnerability by sending a crafted IPv6 packet to an affected device with the goal of reaching the vulnerable section of the input buffer. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition. This vulnerability is specific to IPv6 traffic. IPv4 traffic is not affected.
How severe is CVE-2020-3500?: CVE-2020-3500 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2020-3500 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-3500?: CVE-2020-3500 affects Cisco Staros. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-3500?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-3500 published?: CVE-2020-3500 was published on 2020-08-17 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asr5k-ipv6-dos-ce3zhF8m

Affected products (1)

cpe:2.3:o:cisco:staros:*:*:*:*:*:*:*:*

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