Detect Microsoft Windows Type Confusion Vulnerability (CVE-2026-21519) in Sumo Logic CSE
Detects exploitation of CVE-2026-21519, a type confusion vulnerability (CWE-843) in Microsoft Windows. Type confusion vulnerabilities occur when code allocates or initializes a resource using one type but accesses it using an incompatible type, leading to out-of-bounds memory access, arbitrary code execution, or privilege escalation. This CVE is listed on the CISA Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.
MITRE ATT&CK
Sumo Detection Query
_sourceCategory=windows/security OR _sourceCategory=windows/sysmon
| parse field=_raw "EventCode=*" as event_id nodrop
| parse field=_raw "Image=*\n" as process_image nodrop
| parse field=_raw "ParentImage=*\n" as parent_image nodrop
| parse field=_raw "CommandLine=*\n" as cmdline nodrop
| parse field=_raw "ImagePath=*\n" as service_path nodrop
| where (
(event_id in ("4688", "4697", "7045") and (
cmdline matches "*SeDebugPrivilege*"
or cmdline matches "*SeImpersonatePrivilege*"
or service_path matches "*\\AppData\\*"
or service_path matches "*\\Temp\\*"
or service_path matches "*.tmp*"
))
or (event_id = "6" and not (process_image matches "*MsMpEng.exe*" or process_image matches "*services.exe*" or process_image matches "*wininit.exe*"))
or (event_id = "1" and (parent_image matches "*lsass.exe*" or parent_image matches "*winlogon.exe*" or parent_image matches "*csrss.exe*") and not (process_image matches "*conhost.exe*" or process_image matches "*werfault.exe*"))
)
| eval risk_score = if(event_id = "6" and not (process_image matches "*services.exe*"), 90, if(event_id = "1" and parent_image matches "*lsass.exe*", 85, 60))
| fields _messagetime, _sourceHost, event_id, process_image, parent_image, cmdline, service_path, risk_score
| sort by risk_score, _messagetimeSumo Logic query detecting CVE-2026-21519 type confusion exploitation indicators via Windows Security and Sysmon logs, identifying privilege abuse, suspicious service file paths, driver loads from untrusted initiators, and anomalous child processes.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate antivirus and EDR products performing kernel-level monitoring operations
- Software deployment agents staging installers temporarily in AppData or Temp directories
- Helpdesk remote management tools spawning processes under system parent processes
- Performance monitoring tools requesting SeDebugPrivilege for authorized process inspection
Other platforms for CVE-2026-21519
Testing Methodology
Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Simulate Anomalous Child Process from Winlogon
Expected signal: Sysmon EventID 1 showing cmd.exe or similar process with an unexpected parent, Windows Security EventID 4688 capturing the new process creation with command line arguments.
- Test 2Privilege Token Enumeration via Command Line
Expected signal: Windows Security EventID 4688 with CommandLine containing privilege-related arguments, Sysmon EventID 1 capturing the full process creation with integrity level.
- Test 3Suspicious Service Installation from Temp Directory
Expected signal: Windows System EventID 7045 (new service installed) with ServiceImagePath pointing to %TEMP%, Sysmon EventID 13 capturing registry writes for the new service key under HKLM\SYSTEM\CurrentControlSet\Services.
- Test 4Unsigned Driver Load Simulation via Sysmon
Expected signal: Sysmon EventID 6 (DriverLoad) with the ImageLoaded path pointing to a non-standard location and the initiating process being a user-mode application rather than services.exe or wininit.exe.
Unlock Pro Content
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