What is CVE-2020-0839?

An elevation of privilege vulnerability exists in the way that the dnsrslvr.dll handles objects in memory. An attacker who successfully exploited the vulnerability could execute code with elevated permissions. To exploit the vulnerability, a locally authenticated attacker could run a specially crafted application. The security update addresses the vulnerability by ensuring the dnsrslvr.dll properly handles objects in memory.

How severe is CVE-2020-0839?

CVE-2020-0839 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-0839 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-0839?

CVE-2020-0839 primarily affects Microsoft Windows 10. In total, 15 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-0839?

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-2020-0839 published?

CVE-2020-0839 was published on 2020-09-11 and last updated on 2026-06-17.

CVE-2020-0839

CVE-2020-0839 is a high-severity vulnerability in Microsoft Windows 10 with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 4.6
EPSS exploit prediction: 1% (56th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Microsoft Windows 10
Published: 2020-09-11
Last modified: 2026-06-17

Description

An elevation of privilege vulnerability exists in the way that the dnsrslvr.dll handles objects in memory. An attacker who successfully exploited the vulnerability could execute code with elevated permissions. To exploit the vulnerability, a locally authenticated attacker could run a specially crafted application. The security update addresses the vulnerability by ensuring the dnsrslvr.dll properly handles objects in memory.

Frequently asked questions

What is CVE-2020-0839?: An elevation of privilege vulnerability exists in the way that the dnsrslvr.dll handles objects in memory. An attacker who successfully exploited the vulnerability could execute code with elevated permissions. To exploit the vulnerability, a locally authenticated attacker could run a specially crafted application. The security update addresses the vulnerability by ensuring the dnsrslvr.dll properly handles objects in memory.
How severe is CVE-2020-0839?: CVE-2020-0839 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-0839 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-0839?: CVE-2020-0839 primarily affects Microsoft Windows 10. In total, 15 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-0839?: 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-2020-0839 published?: CVE-2020-0839 was published on 2020-09-11 and last updated on 2026-06-17.

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-0839

Affected products (15)

cpe:2.3:o:microsoft:windows_10:-:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10:-:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10:1607:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10:1607:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10:1709:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10:1803:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10:1809:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10:1903:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10:1909:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_10:2004:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:-:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:1903:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:1909:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2016:2004:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:*

More vulnerabilities in Microsoft Windows 10

CVE-2020-1467 — Critical (CVSS 10.0): An elevation of privilege vulnerability exists when Windows improperly handles hard links. An attacker who successfully…
CVE-2021-26424 — Critical (CVSS 9.9): Windows TCP/IP Remote Code Execution Vulnerability
CVE-2021-28476 — Critical (CVSS 9.9): Windows Hyper-V Remote Code Execution Vulnerability
CVE-2021-26867 — Critical (CVSS 9.9): Windows Hyper-V Remote Code Execution Vulnerability
CVE-2020-1112 — Critical (CVSS 9.9): An elevation of privilege vulnerability exists when the Windows Background Intelligent Transfer Service (BITS) IIS…
CVE-2019-1384 — Critical (CVSS 9.9): A security feature bypass vulnerability exists where a NETLOGON message is able to obtain the session key and sign…

All CVEs affecting Microsoft Windows 10 →