CVE-2025-21440 — Windows NTLM Auth Bypass¶
Key facts
CVE-2025-21440 is a Critical vulnerability: Windows NTLM Auth Bypass. This entry ships a detection-only PoC.
| CVE | CVE-2025-21440 |
| Severity | Critical |
| Detection / prevention | — |
| PoC | poc.py |
| Source | 2025/CVE-2025-21440/ |
Details¶
Overview¶
Windows NTLM auth bypass vulnerability
Details¶
- CVE ID: CVE-2025-21440
- CVSS Score: 9.8 (Critical)
- Type: Auth Bypass
- Product: Windows NTLM
Usage¶
References¶
Frequently asked questions¶
What is CVE-2025-21440?¶
CVE-2025-21440 is a Critical vulnerability: Windows NTLM Auth Bypass. This entry ships a detection-only PoC.
How do I detect CVE-2025-21440?¶
Run the detection-only PoC included with this entry against your Docker test lab to confirm whether a target is affected; pair it with your own IDS logging.
How do I block or mitigate CVE-2025-21440?¶
Upgrade to a fixed version per the vendor advisory; the NVD record lists the affected versions. Use the included PoC to verify your remediation.
For authorized security testing and research only. See the full source and NVD record.