How severe is CVE-2026-42837?

CVE-2026-42837 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-2026-42837 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-2026-42837?

CVE-2026-42837 primarily affects Microsoft Windows 10 1809. In total, 19 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-42837?

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.

Does CVE-2026-42837 have an EU (EUVD) identifier?

Yes. CVE-2026-42837 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35591.

When was CVE-2026-42837 published?

CVE-2026-42837 was published on 2026-06-09 and last updated on 2026-06-17.

CVE-2026-42837

CVE-2026-42837 is a high-severity vulnerability in Microsoft Windows 10 1809 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. The underlying weakness is classified as CWE-125.

Key facts

Severity: High (CVSS 3.x base score 7.8)
EPSS exploit prediction: 0% (24th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-35591
Weakness: CWE-125
Affected product: Microsoft Windows 10 1809
Published: 2026-06-09
Last modified: 2026-06-17

Description

Buffer over-read in Windows Projected File System Filter Driver allows an authorized attacker to elevate privileges locally.

Frequently asked questions

What is CVE-2026-42837?: Buffer over-read in Windows Projected File System Filter Driver allows an authorized attacker to elevate privileges locally.
How severe is CVE-2026-42837?: CVE-2026-42837 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-2026-42837 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-2026-42837?: CVE-2026-42837 primarily affects Microsoft Windows 10 1809. In total, 19 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-42837?: 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.
Does CVE-2026-42837 have an EU (EUVD) identifier?: Yes. CVE-2026-42837 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35591.
When was CVE-2026-42837 published?: CVE-2026-42837 was published on 2026-06-09 and last updated on 2026-06-17.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42837

Affected products (19)

cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:*

More vulnerabilities in Microsoft Windows 10 1809

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Other CWE-125 (Out-of-bounds Read) vulnerabilities

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CVE-2021-41556 — Critical (CVSS 10.0): sqclass.cpp in Squirrel through 2.2.5 and 3.x through 3.1 allows an out-of-bounds read (in the core interpreter) that…
CVE-2021-21777 — Critical (CVSS 10.0): An information disclosure vulnerability exists in the Ethernet/IP UDP handler functionality of EIP Stack Group OpENer…
CVE-2017-14451 — Critical (CVSS 10.0): An exploitable out-of-bounds read vulnerability exists in libevm (Ethereum Virtual Machine) of CPP-Ethereum. A…
CVE-2013-0767 — Critical (CVSS 10.0): The nsSVGPathElement::GetPathLengthScale function in Mozilla Firefox before 18.0, Firefox ESR 10.x before 10.0.12 and…

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