Security Resilience

CVE-2026-83869

Memory Safety in Microsoft Windows 10 21H2 ≤ 10.0.19044.7807

Memory Safety
Published
13 October 2026
Modified
16 October 2026
Patch / advisory
View advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0065 50th percentile
Risk Priority 72 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-83869 is a critical-severity Wrap or Wraparound (CWE-191) vulnerability in Microsoft Windows 10 21H2. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique LSASS Memory (T1003.001); ranked at the 50th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

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

CWE(s)
CWE-191

Related Threats

MITRE ATT&CK Enterprise Techniques

T1003.001 LSASS Memory Credential Access
Adversaries may attempt to access credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS).
attack.mitre.org →
T1003.003 NTDS Credential Access
Adversaries may attempt to access or create a copy of the Active Directory domain database in order to steal credential information, as well as obtain other information about domain members such as devices, users, and access rights.
attack.mitre.org →
T1003.005 Cached Domain Credentials Credential Access
Adversaries may attempt to access cached domain credentials used to allow authentication to occur in the event a domain controller is unavailable.
attack.mitre.org →
T1003.008 /etc/passwd and /etc/shadow Credential Access
Adversaries may attempt to dump the contents of <code>/etc/passwd</code> and <code>/etc/shadow</code> to enable offline password cracking.
attack.mitre.org →
T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
attack.mitre.org →
T1008 Fallback Channels Command And Control
Adversaries may use fallback or alternate communication channels if the primary channel is compromised or inaccessible in order to maintain reliable command and control and to avoid data transfer thresholds.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-52471Shared CWE-191
CVE-2025-21134Shared CWE-191
CVE-2023-39414Shared CWE-191
CVE-2026-29008Shared CWE-191
CVE-2024-38050Shared CWE-191
CVE-2024-10838Shared CWE-191
CVE-2023-24864Shared CWE-191
CVE-2024-30070Shared CWE-191
CVE-2026-69269Shared CWE-191
CVE-2026-37231Shared CWE-191

Affected Assets

microsoft
windows 10 1607
≤ 10.0.14393.9612 · ≤ 10.0.14393.9612
microsoft
windows 10 1809
≤ 10.0.17763.9376 · ≤ 10.0.17763.9376
microsoft
windows 10 21h2
≤ 10.0.19044.7807 · ≤ 10.0.19044.7807 · ≤ 10.0.19044.7807
microsoft
windows 10 22h2
≤ 10.0.19045.7807 · ≤ 10.0.19045.7807 · ≤ 10.0.19045.7807
microsoft
windows 11 23h2
≤ 10.0.22631.7652 · ≤ 10.0.22631.7652
microsoft
windows 11 24h2
≤ 10.0.26100.9711 · ≤ 10.0.26100.9711
microsoft
windows 11 25h2
≤ 10.0.26200.9711 · ≤ 10.0.26200.9711
microsoft
windows 11 26h1
≤ 10.0.28000.3231 · ≤ 10.0.28000.3231
microsoft
windows 11 26h2
≤ 10.0.26300.9711 · ≤ 10.0.26300.9711
microsoft
windows server 2012
all versions, r2
+4 more product configuration(s) — see NVD for full list

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation partial match

Developer testing and static/dynamic analysis directly find integer underflow defects before code is released.

SA-8 Security and Privacy Engineering Principles partial match

Security engineering principles require use of safe arithmetic constructs or language features that structurally eliminate integer underflow during subtraction.

SI-10 Information Input Validation partial match

Input validation can reject or sanitize values that would cause a subtraction to underflow the representable range.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

ID.RA-01 partial match
blocks

Vulnerability scanning and code analysis can surface underflow flaws after they are introduced.

PR.PS-02 partial match
blocks

Routine patching can remediate known underflow bugs once they are discovered in deployed software.

PR.PS-06 partial match
blocks

Secure SDLC practices directly prevent integer underflow defects via input validation, bounds checking, and static analysis.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.8.10 Information deletion partial match
removes

References