CVE-2026-21525
published 2026-02-10CVE-2026-21525: Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.
PriorityP180medium6.2CVSS 3.1
AVLACLPRNUINSUCNINAH
KEVITW
CISA Known Exploited Vulnerabilitydue 2026-03-03
Exploited in the wild
EPSS
4.96%
91.3th percentile
Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.
Affected
42 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| microsoft | windows_10_1607 | < 10.0.14393.8868 | 10.0.14393.8868 |
| microsoft | windows_10_1809 | < 10.0.17763.8389 | 10.0.17763.8389 |
| microsoft | windows_10_21h2 | < 10.0.19044.6937 | 10.0.19044.6937 |
| microsoft | windows_10_22h2 | < 10.0.19045.6937 | 10.0.19045.6937 |
| microsoft | windows_10_version_1607 | >= 10.0.14393.0 < 10.0.14393.8868 | 10.0.14393.8868 |
| microsoft | windows_10_version_1809 | >= 10.0.17763.0 < 10.0.17763.8389 | 10.0.17763.8389 |
| microsoft | windows_10_version_21h2 | >= 10.0.19044.0 < 10.0.19044.6937 | 10.0.19044.6937 |
| microsoft | windows_10_version_22h2 | >= 10.0.19045.0 < 10.0.19045.6937 | 10.0.19045.6937 |
| microsoft | windows_11_23h2 | < 10.0.22631.6649 | 10.0.22631.6649 |
| microsoft | windows_11_24h2 | < 10.0.26100.7781 | 10.0.26100.7781 |
| microsoft | windows_11_25h2 | < 10.0.26200.7781 | 10.0.26200.7781 |
| microsoft | windows_11_version_22h3 | >= 10.0.22631.0 < 10.0.22631.6649 | 10.0.22631.6649 |
| microsoft | windows_11_version_23h2 | >= 10.0.22631.0 < 10.0.22631.6649 | 10.0.22631.6649 |
| microsoft | windows_11_version_24h2 | >= 10.0.26100.0 < 10.0.26100.7840 | 10.0.26100.7840 |
| microsoft | windows_11_version_25h2 | >= 10.0.26200.0 < 10.0.26200.7840 | 10.0.26200.7840 |
| microsoft | windows_11_version_26h1 | >= 10.0.28000.0 < 10.0.28000.1575 | 10.0.28000.1575 |
| microsoft | windows_server_2012 | — | — |
| microsoft | windows_server_2012 | >= 6.2.9200.0 < 6.2.9200.25923 | 6.2.9200.25923 |
| microsoft | windows_server_2012_r2 | >= 6.3.9600.0 < 6.3.9600.23022 | 6.3.9600.23022 |
| microsoft | windows_server_2016 | < 10.0.14393.8868 | 10.0.14393.8868 |
| microsoft | windows_server_2016 | >= 10.0.14393.0 < 10.0.14393.8868 | 10.0.14393.8868 |
| microsoft | windows_server_2019 | < 10.0.17763.8389 | 10.0.17763.8389 |
| microsoft | windows_server_2019 | >= 10.0.17763.0 < 10.0.17763.8389 | 10.0.17763.8389 |
| microsoft | windows_server_2022 | < 10.0.20348.4711 | 10.0.20348.4711 |
| microsoft | windows_server_2022 | >= 10.0.20348.0 < 10.0.20348.4773 | 10.0.20348.4773 |
Detection & IOCsextracted from sources · hover to see the quote
- →Target component is Windows Remote Access Connection Manager (RASMAN); monitor for unexpected service crashes or null pointer dereference-related system crashes (BSODs) in this service, which may indicate local exploitation attempts. ↗
- →Exploitation has been detected in the wild (per MSRC); treat any RASMAN service crash or denial-of-service event on unpatched systems as a high-priority incident. ↗
- →CVE is listed in CISA KEV with a remediation due date of 2026-03-03; prioritize detection and patching on systems running Windows Remote Access Connection Manager. ↗
- ·Attack vector is local; exploitation requires the attacker to already have local access to the target system to trigger the denial of service. ↗
- ·Multiple KB patches are available across different Windows versions; ensure the correct KB is applied for the specific OS version in scope. ↗
CVSS provenance
nvdv3.16.2MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
vulncheck6.2MEDIUM
cisa6.2MEDIUM
vendor_msrc6.2MEDIUM
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CISA
Microsoft Windows NULL Pointer Dereference Vulnerability
cisa·2026-02-10·CVSS 6.2
CVE-2026-21525 [MEDIUM] CWE-476 Microsoft Windows NULL Pointer Dereference Vulnerability
Vulnerability: Microsoft Windows NULL Pointer Dereference Vulnerability
Affected: Microsoft Windows
Microsoft Windows Remote Access Connection Manager contains a NULL pointer dereference that could allow an unauthorized attacker to deny service locally.
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.
Notes: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21525 ; https://nvd.nist.gov/vuln/detail/CVE-2026-21525
Remediation Due Date: 2026-03-03
Microsoft
Windows Remote Access Connection Manager Denial of Service Vulnerability
vendor_msrc·2026-02-10·CVSS 6.2
CVE-2026-21525 [MEDIUM] CWE-476 Windows Remote Access Connection Manager Denial of Service Vulnerability
Windows Remote Access Connection Manager Denial of Service Vulnerability
Description: Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.
Windows Remote Access Connection Manager: Windows Remote Access Connection Manager
Microsoft: Microsoft
Customer Action Required: Yes
Impact: Denial of Service
Exploit Status: Publicly Disclosed:No;Exploited:Yes;Latest Software Release:Exploitation Detected
Reference: https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5075904
Reference: https://support.microsoft.com/help/5075904
Reference: https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5075906
Reference: https://support.microsoft.com/help/5075906
Reference: https://catalog.update.microsoft.com/v7/
GHSA
GHSA-cf8p-vhmm-h7g6: Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally
ghsa_unreviewed·2026-02-10
CVE-2026-21525 [MEDIUM] CWE-476 GHSA-cf8p-vhmm-h7g6: Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally
Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.
VulnCheck
Microsoft Windows NULL Pointer Dereference Vulnerability
vulncheck·2026·CVSS 6.2
CVE-2026-21525 [MEDIUM] CWE-476 Microsoft Windows NULL Pointer Dereference Vulnerability
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.
Affected: Microsoft Windows
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.
Exploitation References: https://api.msrc.microsoft.com/cvrf/v3.0/cvrf/2026-Feb; https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21525; https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json; https://www.recordedfuture.com/blog/february-2026-cve-landscape
Remediation Due: 2026-03-03
No detection rules found.
No public exploits indexed.
Sophos
February’s Patch Tuesday assumes battle stations
blogs_sophos·2026-02-13
February’s Patch Tuesday assumes battle stations
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Qualys
Microsoft and Adobe Patch Tuesday, February 2026 Security Update Review
blogs_qualys·2026-02-10
Microsoft and Adobe Patch Tuesday, February 2026 Security Update Review
## Table of Contents
Microsoft Patch Tuesday forFebruary2026
Adobe Patches for February 2026
Zero-day Vulnerabilities Patched inFebruaryPatch Tuesday Edition
Critical Severity Vulnerabilities Patched inFebruaryPatch Tuesday Edition
Other Microsoft Vulnerability Highlights
Microsoft Release Summary
Discover and Prioritize Vulnerabilities inVulnerability Management, Detection & Response (VMDR)
Rapid Response with TruRisk Eliminate
Qualys Monthly Webinar Series
Microsoft’s February 2026 Patch Tuesday focuses on closing security gaps that attackers could exploit, reinforcing the importance of timely patching in enterprise environments. Here’s a quick breakdown of what you need to know.
## Microsoft Patch Tuesday for February 2026
This month’s release addresses 61 vulnerabilities, i
Bleepingcomputer
Microsoft February 2026 Patch Tuesday fixes 6 zero-days, 58 flaws
blogs_bleepingcomputer·2026-02-10·CVSS 8.8
[HIGH] Microsoft February 2026 Patch Tuesday fixes 6 zero-days, 58 flaws
## Microsoft February 2026 Patch Tuesday fixes 6 zero-days, 58 flaws
## Lawrence Abrams
25 Elevation of Privilege vulnerabilities
5 Security Feature Bypass vulnerabilities
12 Remote Code Execution vulnerabilities
6 Information Disclosure vulnerabilities
3 Denial of Service vulnerabilities
7 Spoofing vulnerabilities
When BleepingComputer reports on Patch Tuesday security updates, we only count those released by Microsoft today. Therefore, the number of flaws does not include 3 Microsoft Edge flaws fixed earlier this month.
As part of these updates, Microsoft has also begun to roll out updated Secure Boot certificates to replace the original 2011 certificates that are expiring in late June 2026.
"With this update, Windows quality updates include a broad set of targeting data that i
Krebs
Patch Tuesday, February 2026 Edition
blogs_krebs·2026-02-10·CVSS 7.8
CVE-2026-21510 [HIGH] Patch Tuesday, February 2026 Edition
Microsoft today released updates to fix more than 50 security holes in its Windows operating systems and other software, including patches for a whopping six “zero-day” vulnerabilities that attackers are already exploiting in the wild.
Zero-day #1 this month is CVE-2026-21510, a security feature bypass vulnerability in Windows Shell wherein a single click on a malicious link can quietly bypass Windows protections and run attacker-controlled content without warning or consent dialogs. CVE-2026-21510 affects all currently supported versions of Windows.
The zero-day flaw CVE-2026-21513 is a security bypass bug targeting MSHTML, the proprietary engine of the default Web browser in Windows. CVE-2026-21514 is a related security feature bypass in Microsoft Word.
The zero-day CVE-2026-21533 all
Talos
Microsoft Patch Tuesday for February 2026 — Snort rules and prominent vulnerabilities
blogs_talos·2026-02-10·CVSS 8.8
CVE-2026-21522 [HIGH] Microsoft Patch Tuesday for February 2026 — Snort rules and prominent vulnerabilities
## Microsoft Patch Tuesday for February 2026 — Snort rules and prominent vulnerabilities
Microsoft has released its monthly security update for February 2026, which includes 59 vulnerabilities affecting a range of products, including two that Microsoft marked as “Critical”.
CVE-2026-21522 is a critical elevation of privilege vulnerability affecting Microsoft ACI Confidential Containers. Successful exploitation of this vulnerability could enable an authorized attacker to escalate privileges on affected systems. This vulnerability is not listed as publicly disclosed and received a CVSS 3.1 score of 6.7.
CVE-2026-23655 is a critical information disclosure vulnerability affecting Microsoft ACI Confidential Containers. This vulnerability could enable an authorized attacker to disclose sensit
Qualys
Microsoft and Adobe Patch Tuesday, February 2026 Security Update Review | Qualys
blogs_qualys·2026-02-10
Microsoft and Adobe Patch Tuesday, February 2026 Security Update Review | Qualys
#### Table of Contents
- Microsoft Patch Tuesday forFebruary2026
- Adobe Patches for February 2026
- Zero-day Vulnerabilities Patched inFebruaryPatch Tuesday Edition
- Critical Severity Vulnerabilities Patched inFebruaryPatch Tuesday Edition
- Other Microsoft Vulnerability Highlights
- Microsoft Release Summary
- Discover and Prioritize Vulnerabilities inVulnerability Management, Detection & Response (VMDR)
- Rapid Response with TruRisk Eliminate
- Qualys Monthly Webinar Series
Microsoft’s February 2026 Patch Tuesday focuses on closing security gaps that attackers could exploit, reinforcing the importance of timely patching in enterprise environments. Here’s a quick breakdown of what you need to know.
## Microsoft Patch Tuesday for February 2026
This month’s release addresses 61 vulner
Krebs
Patch Tuesday, February 2026 Edition
blogs_krebs·2026-02-10·CVSS 7.8
CVE-2026-21510 [HIGH] Patch Tuesday, February 2026 Edition
Microsoft today released updates to fix more than 50 security holes in its Windows operating systems and other software, including patches for a whopping six “zero-day” vulnerabilities that attackers are already exploiting in the wild.
Zero-day #1 this month is CVE-2026-21510 , a security feature bypass vulnerability in Windows Shell wherein a single click on a malicious link can quietly bypass Windows protections and run attacker-controlled content without warning or consent dialogs. CVE-2026-21510 affects all currently supported versions of Windows.
The zero-day flaw CVE-2026-21513 is a security bypass bug targeting MSHTML , the proprietary engine of the default Web browser in Windows. CVE-2026-21514 is a related security feature bypass in Microsoft Word.
The zero-day CVE-2026-21533 a
Tenable
February 2026 Microsoft Patch Tuesday | Tenable®
blogs_tenable·2026-02-10
February 2026 Microsoft Patch Tuesday | Tenable®
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Talos
Microsoft Patch Tuesday for February 2026 — Snort rules and prominent vulnerabilities
blogs_talos·2026-02-10·CVSS 8.8
CVE-2026-21522 [HIGH] Microsoft Patch Tuesday for February 2026 — Snort rules and prominent vulnerabilities
Microsoft has released its monthly security update for February 2026, which includes 59 vulnerabilities affecting a range of products, including two that Microsoft marked as “Critical”.
CVE-2026-21522 is a critical elevation of privilege vulnerability affecting Microsoft ACI Confidential Containers. Successful exploitation of this vulnerability could enable an authorized attacker to escalate privileges on affected systems. This vulnerability is not listed as publicly disclosed and received a CVSS 3.1 score of 6.7.
CVE-2026-23655 is a critical information disclosure vulnerability affecting Microsoft ACI Confidential Containers. This vulnerability could enable an authorized attacker to disclose sensitive information including secret tokens and keys if successfully exploited. This vulnerabi
Zscaler
Zscaler protects against 9 new vulnerabilities | 02-10-2026
blogs_zscaler·CVSS 7.8
[HIGH] Zscaler protects against 9 new vulnerabilities | 02-10-2026
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Wiz
CVE-2026-21525 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 6.2
CVE-2026-21525 [MEDIUM] CVE-2026-21525 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-21525 :
vulnerability analysis and mitigation
Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service locally.
Source : NVD
## 6.2
Score
Published February 10, 2026
Severity MEDIUM
CNA Score 6.2
Has Public Exploit Yes
Has CISA KEV Exploit Yes
CISA KEV Release Date N/A
CISA KEV Due Date N/A
Exploitation Probability Percentile (EPSS) 94.2
Exploitation Probability (EPSS) 13.4
Sources
NVD
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Recorded Future
February 2026 CVE Landscape: 13 Critical Vulnerabilities Mark 43% Drop from January
blogs_recorded_future·CVSS 7.7
[HIGH] February 2026 CVE Landscape: 13 Critical Vulnerabilities Mark 43% Drop from January
# February 2026 CVE Landscape:13 Critical Vulnerabilities Mark 43% Drop from January
February 2026 saw a 43% decrease in high-impact vulnerabilities, with Recorded Future's Insikt Group® identifying 13 vulnerabilities requiring immediate remediation, down from 23 in January 2026. All 13 carried a ‘Very Critical’ Recorded Future Risk Score.
What security teams need to know:
- Microsoft dominates: Six of 13 vulnerabilities affected Microsoft products, accounting for 46% of February's findings; all were added to CISA's KEV catalog on the same day
- Supply-chain attack on Notepad++: Lotus Blossom, a suspected China state-sponsored threat actor, exploited CVE-2025-15556 to hijack Notepad++'s update channel and deliver a Cobalt Strike Beacon and the Chrysalis backdoor
- APT28 exploits MSHTML
Sophos
February’s Patch Tuesday assumes battle stations
blogs_sophos
February’s Patch Tuesday assumes battle stations
Share This
Microsoft on Tuesday released 58 patches affecting 15 product families. Five of the addressed issues, all involving Azure, are considered by Microsoft to be of Critical severity, though only two require urgent attention (more on that below). Fifteen have a CVSS base score of 8.0 or higher, including two with a 9.8 base score. Six are known to be under active exploit in the wild, and three are publicly disclosed (including one not yet known to be under exploit).
At patch time, five CVEs are judged more likely to be exploited in the next 30 days by the company’s estimation, in addition to the six already detected to be so. Various of this month’s issues are amenable to direct detection by Sophos protections, and we include information on those in a table below. The release also
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21525https://www.vicarius.io/vsociety/posts/cve-2026-21525-detection-script-dos-vulnerability-in-windows-remote-access-connection-managerhttps://www.vicarius.io/vsociety/posts/cve-2026-21525-mitigation-script-dos-vulnerability-in-windows-remote-access-connection-managerhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21525
2026-02-10
Published
2026-02-10
Added to CISA KEV
Exploited in the wild