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CVE-2026-21525 CISA KEV — actively exploited

Microsoft Windows NULL Pointer Dereference Vulnerability

Microsoft — Windows 10 Version 1607

Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.

CVSS scoreMedium

6.2

EPSS — exploitation probabilityLow

5.0%

Vector breakdown

Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C

Published
Feb 10, 2026
Modified
May 11, 2026
Added to KEV
Feb 10, 2026
Federal patch due
Mar 3, 2026

CISA required action

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Weakness classification

CWE-476NULL Pointer Dereference

Proof-of-concept & exploitation references

Weaponization

Nuclei template

Not found

Metasploit module

Not found

Public repositories whose name or description references CVE-2026-21525, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit - cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.

No public GitHub repositories referencing CVE-2026-21525 were found at last check. Absence here is not proof no exploit exists - see the references below for vendor advisories and write-ups.

References

  • msrc.microsoft.com

Frequently asked questions

What is CVE-2026-21525?

Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.

How severe is CVE-2026-21525?

CVE-2026-21525 has a CVSS base score of 6.2 out of 10 (CVSS 3.1).

Is CVE-2026-21525 actively exploited in the wild?

Yes. CVE-2026-21525 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Feb 10, 2026, meaning CISA has confirmed evidence of active exploitation.

What is the EPSS score for CVE-2026-21525?

5.0% - meaning FIRST.org's EPSS model estimates a 5.0% probability this vulnerability will be exploited in the wild within 30 days (91% percentile among all scored CVEs).

What type of vulnerability is CVE-2026-21525?

CVE-2026-21525 is classified under CWE-476 (CWE-476: NULL Pointer Dereference).

Cross-checked against

  • NVD (NIST)
  • MITRE CVE Record
  • CISA KEV
  • FIRST.org EPSS
  • GitHub Advisory Database
  • GitHub public repository search

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