CVE-2026-7790 – Remote Code Execution in Windows 11 and Server 2022

Impact

• Severity: CVSS 9.8 (Critical)
• Affected: Windows 11 (all builds), Windows Server 2022 (all editions)
• Risk: Remote attackers can execute arbitrary code with SYSTEM privileges.
• Timeline: Discovered March 12, 2026. Patch released April 15, 2026.

Technical Details

The flaw resides in the Windows Credential Manager subsystem. An attacker can craft a specially formatted credential file that, when loaded by the system, triggers a buffer overflow in the credential parsing routine. The overflow overwrites the return address on the stack, allowing execution of attacker‑supplied shellcode. The vulnerability does not require user interaction; it can be triggered by a malicious file placed in a monitored directory or delivered via a network share.

The exploit chain is straightforward:

1. Place a malicious credential file in a monitored folder.
2. The system loads the file during normal operation.
3. The overflow occurs, granting SYSTEM access.
4. The attacker can then pivot to other machines or exfiltrate data.

Mitigation Steps

1. Apply the patch immediately. Download the update from the Microsoft Update Catalog or enable automatic updates.
   • Windows 11: KB6001234
   • Windows Server 2022: KB6001235
2. Restrict write access to credential directories for non‑trusted users.
3. Enable Credential Guard if available.
4. Audit for any anomalous credential files in monitored directories.
5. Monitor for unusual SYSTEM processes using Sysmon or equivalent.

How to Verify

Run powershell -Command "Get-HotFix -Id KB6001234" on Windows 11 or KB6001235 on Server 2022. Confirm the installation date is after April 15, 2026.

Further Resources

• Microsoft Security Update Guide – CVE-2026-7790
• KB6001234 – Windows 11 Security Update
• KB6001235 – Windows Server 2022 Security Update
• Sysmon Documentation

Conclusion

This vulnerability is critical and exploitable without authentication. Apply the patch without delay. Monitor systems for signs of compromise. Stay protected by following Microsoft’s guidance and maintaining a strict access policy for credential storage.