Critical CVSS 9.8 EPSS 0.01932 2026-05 archive

Executive Summary

Heap-based buffer overflow in Microsoft Windows DNS allows an unauthorized attacker to execute code over a network.

Overview

9.8
CVSS CRITICAL
Critical
MS Severity
Not Exploited
MS Exploit Status
Exploitation Unlikely
MS Exploit Likelihood
Category Remote Code Execution
Released May 12 2026
Last Updated May 12 2026
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.01932 — 0.7739 percentile
NVD CVSS 9.8 CRITICAL — matches MSRC

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
None
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 8.5

EPSS Score

0.01932
probability of exploitation in the next 30 days
0.7739 percentile - updated 2026-06-21
View on FIRST.org

Affected Products

5 affected products
Product KB Article Severity Impact Restart Required
Windows 11 Version 23H2 for ARM64-based Systems 5087420 (Security Update) Critical Remote Code Execution Yes
Windows 11 Version 23H2 for x64-based Systems 5093998 (Security Update) Critical Remote Code Execution Yes
Windows 11 Version 24H2 for ARM64-based Systems 5089549 (Security Update) 5089466 (Security Hotpatch Update) Critical Remote Code Execution 5082063 Base: 9.8 Temporal: 8.5 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26100.8457 10.0.26100.8390 Yes None Windows 11 Version 24H2 for x64-based Systems 5089549 (Security Update) 5089466 (Security Hotpatch Update) Critical Remote Code Execution 5082063 Base: 9.8 Temporal: 8.5 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26100.8457 10.0.26100.8390 Yes None Windows 11 Version 25H2 for ARM64-based Systems 5089549 (Security Update) 5089466 (Security Hotpatch Update) Critical Remote Code Execution 5083769 Base: 9.8 Temporal: 8.5 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26200.8457 10.0.26200.8390 Yes None Windows 11 Version 25H2 for x64-based Systems 5089549 (Security Update) 5089466 (Security Hotpatch Update) Critical Remote Code Execution 5083769 Base: 9.8 Temporal: 8.5 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26200.8457 10.0.26200.8390 Yes None Windows 11 Version 26H1 for ARM64-based Systems 5089548 (Security Update) Critical Remote Code Execution Yes
Windows 11 version 26H1 for x64-based Systems 5089548 (Security Update) Critical Remote Code Execution Yes
Windows Server 2022, 23H2 Edition (Server Core installation) 5087541 (Security Update) Critical Remote Code Execution Yes

Patches

4 patches
Article Type Restart
5087420 Security Update Yes
5093998 Security Update Yes
5089548 Security Update Yes
5087541 Security Update Yes

Known Exploits

Acknowledgments

WARP team at Microsoft