How severe is CVE-2020-6989?

CVE-2020-6989 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-2020-6989 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-6989?

CVE-2020-6989 primarily affects Moxa Pt-7528-24tx-hv Firmware. In total, 55 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-6989?

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-2020-6989 published?

CVE-2020-6989 was published on 2020-03-24 and last updated on 2026-06-17.

CVE-2020-6989

CVE-2020-6989 is a critical-severity vulnerability in Moxa Pt-7528-24tx-hv Firmware 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. The underlying weakness is classified as CWE-787.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 3% (85th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Moxa Pt-7528-24tx-hv Firmware
Published: 2020-03-24
Last modified: 2026-06-17

Description

In Moxa PT-7528 series firmware, Version 4.0 or lower, and PT-7828 series firmware, Version 3.9 or lower, a buffer overflow in the web server allows remote attackers to cause a denial-of-service condition or execute arbitrary code.

Frequently asked questions

What is CVE-2020-6989?: In Moxa PT-7528 series firmware, Version 4.0 or lower, and PT-7828 series firmware, Version 3.9 or lower, a buffer overflow in the web server allows remote attackers to cause a denial-of-service condition or execute arbitrary code.
How severe is CVE-2020-6989?: CVE-2020-6989 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-2020-6989 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-6989?: CVE-2020-6989 primarily affects Moxa Pt-7528-24tx-hv Firmware. In total, 55 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-6989?: 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-2020-6989 published?: CVE-2020-6989 was published on 2020-03-24 and last updated on 2026-06-17.

References

https://www.us-cert.gov/ics/advisories/icsa-20-056-03

Affected products (55)

cpe:2.3:o:moxa:pt-7528-24tx-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-24tx-hv-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-24tx-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-24tx-wv-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-24tx-wv-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-12msc-12tx-4gsfp-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-12msc-12tx-4gsfp-hv-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-12msc-12tx-4gsfp-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-12msc-12tx-4gsfp-wv-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-12mst-12tx-4gsfp-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-12mst-12tx-4gsfp-hv-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-12mst-12tx-4gsfp-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-12mst-12tx-4gsfp-wv-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-16msc-8tx-4gsfp-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-16msc-8tx-4gsfp-hv-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-16msc-8tx-4gsfp-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-16msc-8tx-4gsfp-wv-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-16mst-8tx-4gsfp-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-16mst-8tx-4gsfp-hv-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-16mst-8tx-4gsfp-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-16mst-8tx-4gsfp-wv-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-20msc-4tx-4gsfp-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-20msc-4tx-4gsfp-hv-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-20msc-4tx-4gsfp-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-20msc-4tx-4gsfp-wv-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-20mst-4tx-4gsfp-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-20mst-4tx-4gsfp-hv-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-20mst-4tx-4gsfp-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-20mst-4tx-4gsfp-wv-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-8msc-16tx-4gsfp-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-8msc-16tx-4gsfp-hv-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-8msc-16tx-4gsfp-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-8msc-16tx-4gsfp-wv-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-8mst-16tx-4gsfp-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-8mst-16tx-4gsfp-hv-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-8mst-16tx-4gsfp-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-8mst-16tx-4gsfp-wv-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-8ssc-16tx-4gsfp-hv-hv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7528-8ssc-16tx-4gsfp-wv-wv_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:moxa:pt-7828-f-24_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Moxa Pt-7528-24tx-hv Firmware

CVE-2020-6995 — Critical (CVSS 9.8): In Moxa PT-7528 series firmware, Version 4.0 or lower, and PT-7828 series firmware, Version 3.9 or lower, the…
CVE-2020-6985 — Critical (CVSS 9.8): In Moxa PT-7528 series firmware, Version 4.0 or lower, and PT-7828 series firmware, Version 3.9 or lower, these devices…
CVE-2020-6993 — High (CVSS 7.5): In Moxa PT-7528 series firmware, Version 4.0 or lower, and PT-7828 series firmware, Version 3.9 or lower, an attacker…
CVE-2020-6987 — High (CVSS 7.5): In Moxa PT-7528 series firmware, Version 4.0 or lower, and PT-7828 series firmware, Version 3.9 or lower, the affected…
CVE-2020-6983 — High (CVSS 7.5): In Moxa PT-7528 series firmware, Version 4.0 or lower, and PT-7828 series firmware, Version 3.9 or lower, the affected…

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