CVE-2026-83869

CVE-2026-83869 is a critical-severity vulnerability in Microsoft Windows 10 1607 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-191.

Key facts

• Severity: Critical (CVSS 3.x base score 9.8)
• EPSS exploit prediction: 1% (50th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-191
• Affected product: Microsoft Windows 10 1607
• Published: 2026-10-13
• Last modified: 2026-10-16

Description

Integer underflow (wrap or wraparound) in DNS Server allows an unauthorized attacker to execute code over a network.

Frequently asked questions

What is CVE-2026-83869?

Integer underflow (wrap or wraparound) in DNS Server allows an unauthorized attacker to execute code over a network.

How severe is CVE-2026-83869?

CVE-2026-83869 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-2026-83869 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-83869?

CVE-2026-83869 primarily affects Microsoft Windows 10 1607. In total, 26 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-83869?

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-2026-83869 published?

CVE-2026-83869 was published on 2026-10-13 and last updated on 2026-10-16.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83869

Affected products (26)

• 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_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_11_26h2:*:*:*:*:*:*:arm64:*
• cpe:2.3:o:microsoft:windows_11_26h2:*:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
• cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:x64:*
• cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:*

More vulnerabilities in Microsoft Windows 10 1607

• CVE-2026-57092 — Critical (CVSS 9.9): Use after free in Windows VMSwitch allows an authorized attacker to elevate privileges over a network.
• CVE-2026-97815 — Critical (CVSS 9.8): Heap-based buffer overflow in Windows Error Reporting allows an unauthorized attacker to execute code over a network.
• CVE-2026-97814 — Critical (CVSS 9.8): Heap-based buffer overflow in Windows Text Shaping allows an unauthorized attacker to execute code over a network.
• CVE-2026-97805 — Critical (CVSS 9.8): Out-of-bounds read in Windows Partition Management Driver allows an unauthorized attacker to execute code over a…
• CVE-2026-96934 — Critical (CVSS 9.8): Use after free in Windows DHCP Server allows an unauthorized attacker to execute code over a network.
• CVE-2026-96924 — Critical (CVSS 9.8): Untrusted pointer dereference in Windows OLE allows an unauthorized attacker to execute code over a network.

All CVEs affecting Microsoft Windows 10 1607 →

Other CWE-191 (Integer Underflow) vulnerabilities

• CVE-2007-0063 — Critical (CVSS 10.0): Integer underflow in the DHCP server in EMC VMware Workstation before 5.5.5 Build 56455 and 6.x before 6.0.1 Build…
• CVE-2026-101980 — Critical (CVSS 9.8): An Integer Underflow vulnerability in the kernel of Juniper Networks Junos OS with Extended Echo configured allows an…
• CVE-2026-84411 — Critical (CVSS 9.8): The web management service in affected RouterOS versions contains an integer underflow in its HTTP request body…
• CVE-2026-91103 — Critical (CVSS 9.8): HP has identified and remediated multiple externally reported vulnerabilities within HPLIP. The findings affect several…
• CVE-2026-68123 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: openvswitch: fix GSO userspace truncation…
• CVE-2026-51540 — Critical (CVSS 9.8): OpENer 2.3.0 (master branch up to commit 76b95cf) is vulnerable to a severe memory corruption issue caused by an…

Browse all CWE-191 (Integer Underflow) vulnerabilities →