How severe is CVE-2020-5955?

CVE-2020-5955 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-2020-5955 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-5955?

CVE-2020-5955 affects Insyde Insydeh2o Uefi Bios. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-5955?

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-2020-5955 published?

CVE-2020-5955 was published on 2021-11-03 and last updated on 2026-06-17.

CVE-2020-5955

CVE-2020-5955 is a critical-severity vulnerability in Insyde Insydeh2o Uefi Bios 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.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 1% (69th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Insyde Insydeh2o Uefi Bios
Published: 2021-11-03
Last modified: 2026-06-17

Description

An issue was discovered in Int15MicrocodeSmm in Insyde InsydeH2O before 2021-10-14 on Intel client chipsets. A caller may be able to escalate privileges.

Frequently asked questions

What is CVE-2020-5955?: An issue was discovered in Int15MicrocodeSmm in Insyde InsydeH2O before 2021-10-14 on Intel client chipsets. A caller may be able to escalate privileges.
How severe is CVE-2020-5955?: CVE-2020-5955 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-2020-5955 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-5955?: CVE-2020-5955 affects Insyde Insydeh2o Uefi Bios. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-5955?: 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-2020-5955 published?: CVE-2020-5955 was published on 2021-11-03 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:insyde:insydeh2o_uefi_bios:*:*:*:*:*:*:*:*