ReviewHigh

CVE-2026-62696

Microsoft Windows 10 Version 1607, Windows 10 Version 1809, Windows 10 Version 21H2

Integer underflow (wrap or wraparound) in Windows Program Compatibility Assistant Service allows an authorized attacker to elevate privileges locally.

CVSS: 7.8
EPSS: -
CISA KEV: Not listed
Published: 2026.08.12

PRIORITY ASSESSMENT

Review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability-

Technical severityCVSS 7.8

Vulnerability overview

Integer underflow (wrap or wraparound) in Windows Program Compatibility Assistant Service allows an authorized attacker to elevate privileges locally.

Affected product and versions

Product: Microsoft Windows 10 Version 1607, Windows 10 Version 1809, Windows 10 Version 21H2
Affected versions: >= 10.0.14393.0 < 10.0.14393.9418, >= 10.0.17763.0 < 10.0.17763.9121, >= 10.0.19044.0 < 10.0.19044.7663, >= 10.0.19045.0 < 10.0.19045.7663, >= 10.0.22631.0 < 10.0.22631.7517, >= 10.0.26100.0 < 10.0.26100.9168, >= 10.0.26200.0 < 10.0.26200.9168, >= 10.0.28000.0 < 10.0.28000.2704, >= 10.0.20348.0 < 10.0.20348.5499, >= 10.0.26100.0 < 10.0.26100.33296, < 10.0.17763.9115, < 10.0.26100.9106, < 10.0.26200.9106, < 10.0.20348.5440, < 10.0.26100.33222
Fixed versions: Verify the fixed release separately for each affected product line

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that Microsoft Windows 10 Version 1607, Windows 10 Version 1809, Windows 10 Version 21H2 and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE: CWE-191