How severe is CVE-2020-27339?

CVE-2020-27339 has a CVSS 3.x base score of 6.7, rated medium severity. It is exploitable over local access with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-27339 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-27339?

CVE-2020-27339 primarily affects Insyde Insydeh2o. In total, 17 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-27339?

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

When was CVE-2020-27339 published?

CVE-2020-27339 was published on 2021-06-16 and last updated on 2026-06-17.

CVE-2020-27339

CVE-2020-27339 is a medium-severity vulnerability in Insyde Insydeh2o with a CVSS 3.x base score of 6.7. 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-20.

Key facts

Severity: Medium (CVSS 3.x base score 6.7)
CVSS v2: 7.2
EPSS exploit prediction: 0% (24th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Insyde Insydeh2o
Published: 2021-06-16
Last modified: 2026-06-17

Description

In the kernel in Insyde InsydeH2O 5.x, certain SMM drivers did not correctly validate the CommBuffer and CommBufferSize parameters, allowing callers to corrupt either the firmware or the OS memory. The fixed versions for this issue in the AhciBusDxe, IdeBusDxe, NvmExpressDxe, SdHostDriverDxe, and SdMmcDeviceDxe drivers are 05.16.25, 05.26.25, 05.35.25, 05.43.25, and 05.51.25 (for Kernel 5.1 through 5.5).

Frequently asked questions

What is CVE-2020-27339?: In the kernel in Insyde InsydeH2O 5.x, certain SMM drivers did not correctly validate the CommBuffer and CommBufferSize parameters, allowing callers to corrupt either the firmware or the OS memory. The fixed versions for this issue in the AhciBusDxe, IdeBusDxe, NvmExpressDxe, SdHostDriverDxe, and SdMmcDeviceDxe drivers are 05.16.25, 05.26.25, 05.35.25, 05.43.25, and 05.51.25 (for Kernel 5.1 through 5.5).
How severe is CVE-2020-27339?: CVE-2020-27339 has a CVSS 3.x base score of 6.7, rated medium severity. It is exploitable over local access with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-27339 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-27339?: CVE-2020-27339 primarily affects Insyde Insydeh2o. In total, 17 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-27339?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-27339 published?: CVE-2020-27339 was published on 2021-06-16 and last updated on 2026-06-17.

References

Affected products (17)

cpe:2.3:o:insyde:insydeh2o:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:ruggedcom_apr1808_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_field_pg_m5_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_field_pg_m6_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_ipc127e_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_ipc227g_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_ipc277g_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_ipc327g_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_ipc377g_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_ipc427e_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_ipc477e_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_ipc477e_pro_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_ipc627e_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_ipc647e_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_ipc677e_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_ipc847e_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:simatic_itp1000_firmware:-:*:*:*:*:*:*:*

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