CVE-2026-34343: Windows Application Identity (AppID) Subsystem Elevation of Privilege Vulnerability

Published May 12, 2026
·
Updated

Heap-based buffer overflow in Windows Application Identity (AppID) Subsystem allows an authorized attacker to elevate privileges locally.

Other sources

Windows Application Identity (AppID) Subsystem Elevation of Privilege Vulnerability

— Microsoft

Affected Software

56 affected componentsFixes available
Microsoft Windows 10 1607<10.0.14393.9140
Microsoft Windows 10 1607<10.0.14393.9140
Microsoft Windows 10 1809<10.0.17763.8755
Microsoft Windows 10 1809<10.0.17763.8755
Microsoft Windows 10 21h2<10.0.19044.7291
Microsoft Windows 10 21h2<10.0.19044.7291
Microsoft Windows 10 21h2<10.0.19044.7291
Microsoft Windows 10 22h2<10.0.19045.7291
Microsoft Windows 10 22h2<10.0.19045.7291
Microsoft Windows 10 22h2<10.0.19045.7291
Microsoft Windows 11 23h2<10.0.22631.7079
Microsoft Windows 11 23h2<10.0.22631.7079
Microsoft Windows 11 24h2<10.0.26100.8390
Microsoft Windows 11 24h2<10.0.26100.8390
Microsoft Windows 11 25h2<10.0.26200.8390
Microsoft Windows 11 25h2<10.0.26200.8390
Microsoft Windows 11 26h1<10.0.28000.2113
Microsoft Windows 11 26h1<10.0.28000.2113
Microsoft Windows Server 2012
Microsoft Windows Server 2012=r2
Microsoft Windows Server 2016<10.0.14393.9140
Microsoft Windows Server 2019<10.0.17763.8755
Microsoft Windows Server 2022<10.0.20348.5074
Microsoft Windows Server 2022 23h2<10.0.25398.2330
Microsoft Windows Server 2025<10.0.26100.32772
Microsoft Windows Server 2016<10.0.14393.9140
10.0.14393.9140
Microsoft Windows Server 2012 R2<6.3.9600.23181
6.3.9600.23181
Microsoft Windows 11=26H1
10.0.28000.2113
Microsoft Windows 11=26H1
10.0.28000.2113
Microsoft Windows 11=24H2
10.0.26100.845710.0.26100.8390
Microsoft Windows Server 2012 R2<6.3.9600.23181
6.3.9600.23181
Microsoft Windows Server 2012<6.2.9200.26079
6.2.9200.26079
Microsoft Windows Server 2016<10.0.14393.9140
10.0.14393.9140
Microsoft Windows 10=1607
10.0.14393.9140
Microsoft Windows Server 2025<10.0.26100.32860, <10.0.26100.32772
10.0.26100.3286010.0.26100.32772
Microsoft Windows Server 2012<6.2.9200.26079
6.2.9200.26079
Microsoft Windows 10=1607
10.0.14393.9140
Microsoft Windows 11=23H2
10.0.22631.7079
Microsoft Windows 11=23H2
10.0.22631.7219
Microsoft Windows Server 2022, 23H2 Edition<10.0.25398.2330
10.0.25398.2330
Microsoft Windows 11=24H2
10.0.26100.845710.0.26100.8390
Microsoft Windows Server 2025<10.0.26100.32860, <10.0.26100.32772
10.0.26100.3286010.0.26100.32772
Microsoft Windows 11=25H2
10.0.26200.845710.0.26200.8390
Microsoft Windows 10=22H2
10.0.19045.7417
Microsoft Windows Server 2019<10.0.17763.8755
10.0.17763.8755
Microsoft Windows 11=25H2
10.0.26200.845710.0.26200.8390
Microsoft Windows Server 2022<10.0.20348.5139, <10.0.20348.5074
10.0.20348.513910.0.20348.5074
Microsoft Windows 10=22H2
10.0.19045.7417
Microsoft Windows Server 2022<10.0.20348.5139, <10.0.20348.5074
10.0.20348.513910.0.20348.5074
Microsoft Windows 10=21H2
10.0.19044.7291
Microsoft Windows 10=21H2
10.0.19044.7291
Microsoft Windows 10=1809
10.0.17763.8755
Microsoft Windows 10=1809
10.0.17763.8755
Microsoft Windows 10=21H2
10.0.19044.7291
Microsoft Windows 10=22H2
10.0.19045.7417
Microsoft Windows Server 2019<10.0.17763.8755
10.0.17763.8755

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.14393.9140Patch KB5087537
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.28000.2113Patch KB5089548
  3. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 6.3.9600.23181Patch KB5087471
  4. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.26100.8457Fixed in 10.0.26100.8390Patch KB5089466
  5. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 6.2.9200.26079Patch KB5087470
  6. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.26100.32860Fixed in 10.0.26100.32772Patch KB5087423
  7. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.22631.7079Patch KB5087420
  8. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.22631.7219Patch KB5093998
  9. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.25398.2330Patch KB5087541
  10. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.26200.8457Fixed in 10.0.26200.8390Patch KB5089466
  11. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.19045.7417Patch KB5094127
  12. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.20348.5139Fixed in 10.0.20348.5074Patch KB5087424
  13. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.17763.8755Patch KB5087538
  14. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.19044.7291Patch KB5087544

Event History

May 12, 2026
CVE Published
via Microsoft·02:00 PM
Data Sourced
via Microsoft·02:00 PM
DescriptionSeverityWeakness
Data Sourced
via Microsoft·02:00 PM
Affected Software
Updated
via Microsoft·02:00 PM
Description
CVE Published
via MITRE·04:58 PM
Data Sourced
via MITRE·04:58 PM
DescriptionSeverity
Data Sourced
via NVD·06:17 PM
DescriptionSeverityWeaknessAffected Software
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Frequently Asked Questions

1

What is the severity of CVE-2026-34343?

CVE-2026-34343 has a severity rating that indicates it allows an authorized attacker to elevate privileges locally on affected Windows systems.

2

How do I fix CVE-2026-34343?

To fix CVE-2026-34343, apply the Microsoft security updates provided in the patches relevant to your affected Windows product.

3

Which Windows products are affected by CVE-2026-34343?

CVE-2026-34343 affects various Windows products including Windows Server 2016, Windows Server 2012 R2, Windows 10, and Windows 11.

4

Can CVE-2026-34343 be exploited remotely?

No, CVE-2026-34343 requires local access for exploitation, posing a lower risk than vulnerabilities that can be exploited remotely.

5

What type of vulnerability is CVE-2026-34343?

CVE-2026-34343 is classified as a heap-based buffer overflow vulnerability that can lead to elevation of privilege.

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CVE-2026-34343 - Windows Application Identity (AppID) Subsystem Elevation of Privilege Vulnerability - SecAlerts