Detect Microsoft Windows Type Confusion Vulnerability (CVE-2026-21519) in IBM QRadar
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
QRadar Detection Query
SELECT
DATEFORMAT(devicetime, 'yyyy-MM-dd HH:mm:ss') AS event_time,
logsourcename(logsourceid) AS log_source,
username,
QIDNAME(qid) AS event_name,
"Process Name",
"Parent Process Name",
"Command",
"Service File Name",
magnitude
FROM events
WHERE LOGSOURCETYPENAME(devicetype) IN ('Microsoft Windows Security Event Log', 'Microsoft Windows Sysmon')
AND (
(qid IN (8699022, 8699054) /* EventID 4688 / 4697 */
AND ("Command" ILIKE '%SeDebugPrivilege%'
OR "Command" ILIKE '%SeImpersonatePrivilege%'
OR "Service File Name" ILIKE '%\\AppData\\%'
OR "Service File Name" ILIKE '%\\Temp\\%'
OR "Service File Name" ILIKE '%.tmp%'))
OR (CATEGORYNAME(category) = 'Driver Load'
AND "Process Name" NOT ILIKE '%MsMpEng.exe%'
AND "Process Name" NOT ILIKE '%services.exe%'
AND "Process Name" NOT ILIKE '%wininit.exe%')
OR (CATEGORYNAME(category) = 'Process Launch'
AND ("Parent Process Name" ILIKE '%lsass.exe%'
OR "Parent Process Name" ILIKE '%winlogon.exe%'
OR "Parent Process Name" ILIKE '%csrss.exe%')
AND "Process Name" NOT ILIKE '%conhost.exe%'
AND "Process Name" NOT ILIKE '%werfault.exe%')
)
AND LAST 7 DAYS
ORDER BY magnitude DESC, devicetime DESC
LIMIT 500QRadar AQL query detecting Windows type confusion exploitation indicators across Windows Security Event Log and Sysmon sources, filtering for privilege token manipulation, suspicious service paths, unauthorized driver loads, and anomalous process spawning from protected parent processes.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate endpoint security products triggering driver load events from atypical parent processes
- Enterprise software deployment tools that temporarily stage executables in user profile directories
- System diagnostics tools that spawn child processes from winlogon or csrss legitimately
- Kernel debugging sessions on developer workstations requesting privileged access
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
Get the full detection package for CVE-2026-21519 including response playbook, investigation guide, and atomic red team tests.