CVE-2026-21525
Published: February 10, 2026
Official Description
Microsoft Windows Remote Access Connection Manager contains a NULL pointer dereference that could allow an unauthorized attacker to deny service locally.
CISA KEV Advisory
Microsoft Windows NULL Pointer Dereference Vulnerability
Microsoft Windows Remote Access Connection Manager contains a NULL pointer dereference that could allow an unauthorized attacker to deny service locally.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Risk Analysis
This medium-severity NULL pointer dereference vulnerability in Microsoft Windows Remote Access Connection Manager could allow an unauthorized attacker to cause a local denial of service. While the CVSS score is 6.2, its presence in CISA's KEV catalog confirms active exploitation, indicating it should be addressed promptly.
Active exploitation of this vulnerability has been observed in the wild, and it is listed in CISA's Known Exploited Vulnerabilities catalog.
Apply all available security updates and patches for Microsoft Windows to address the NULL pointer dereference vulnerability in the Remote Access Connection Manager.
Technical Analysis
CVE-2026-21525 requires local access, meaning attackers must already have a foothold on the target system.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A successful exploit results in availability disruption (denial of service), with a CVSS base score of 6.2.
CISA has added CVE-2026-21525 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
News & Research Mentioning CVE-2026-21525
CISA has added six new vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog, based on evidence of active exploitation. CVE-2026-21510 Microsoft Windows Shell Protection Mechanism Failure Vulnerability CVE-2026-21513 Microsoft MSHTML Framework Security Feature Bypass Vulnerability CVE-2026-21514 Microsoft Office Word Reliance on Untrusted Inputs in a Security Decision Vulnerability CVE-2026-21519 Microsoft Windows Type Confusion Vulnerability CVE-2026-21525 Microsoft Windows NULL Pointer Dereference Vulnerability CVE-2026-21533 Windows Remote Desktop Services Elevation of Privilege Vulnerability These types of vulnerabilities are frequent attack vectors for malicious cyber actors and pose significant risks to the federal enterprise. Bi [xlite_meta score:53 src:CISA Alerts xlite_fp:88d5ff4976309c17f8264912552cef85549f24eb7de38b00c6011d2454de9f37]
All References (2)
Quick Facts
Known Threat Actors
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-21525 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1