Executive Summary BlueHammer (CVE-2026-33825) is an eight-stage local privilege-escalation chain targeting the Windows Defender Antimalware Platform before 4.18.26030.3011. It does not grant initial access; an attacker needs standard-user code execution first. Still, in the lab, it reached NT AUTHORITY\SYSTEM, recovered domain-admin credentials from LSASS, and moved laterally via pass-the-hash. This is not memory corruption. It […]

Attackers are exploiting two Microsoft Defender vulnerabilities (CVE-2026-41091 and CVE-2026-45498), Microsoft acknowledged and CISA confirmed by adding them to its Known Exploited Vulnerabilities catalog. The vulnerabilities CVE-2026-41091 allows for local privilege elevation (LPE), and is caused by the Microsoft Malware Protection Engine improperly resolving links before accessing files. “An attacker who successfully exploited this vulnerability could gain SYSTEM privileges,” Microsoft noted. CVE-2026-45498 can cause a denial-of-service (DoS) state, i.e., it can be used to prevent … More → The post Microsoft Defender vulnerabilities exploited in the wild (CVE-2026-41091, CVE-2026-45498) appeared first on Help Net Security .

Microsoft has disclosed that a privilege escalation and a denial-of-service flaw in Defender has come under active exploitation in the wild. The former, tracked as CVE-2026-41091, is rated 7.8 on the CVSS scoring system. Successful exploitation of the flaw could allow an attacker to gain SYSTEM privileges. "Improper link resolution before file access ('link following') in Microsoft Defender

CISA has added seven new vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog , based on evidence of active exploitation. CVE-2008-4250 Microsoft Windows Buffer Overflow Vulnerability CVE-2009-1537 Microsoft DirectX NULL Byte Overwrite Vulnerability CVE-2009-3459 Adobe Acrobat and Reader Heap-Based Buffer Overflow Vulnerability CVE-2010-0249 Microsoft Internet Explorer Use-After-Free Vulnerability CVE-2010-0806 Microsoft Internet Explorer Use-After-Free Vulnerability CVE-2026-41091 Microsoft Defender Elevation of Privilege Vulnerability CVE-2026-45498 Microsoft Defender Denial of Service Vulnerability These types of vulnerabilities are frequent attack vectors for malicious cyber actors and pose significant risks to the federal enterprise. Binding Operational Directive (BOD) 22-01: Reducing the Significant Risk of Known Exploited Vulnerabilities established the KEV Catalog as a living list of known Common Vulnerabilities and Exposures (CVEs) that carry significant risk to the federal enterprise. BOD 22-01 requires Federal Civilian Executive Branch (FCEB) agencies to remediate identified vulnerabilities by the due date to protect FCEB networks against active threats. See the BOD 22-01 Fact Sheet for more information. Although BOD 22-01 only applies to FCEB agencies, CISA strongly urges all organizations to reduce their exposure to cyberattacks by prioritizing timely remediation of KEV Catalog vulnerabilities as part o...

Microsoft Defender contains a link following vulnerability that allows an authorized attacker to elevate privileges locally.

Microsoft Defender contains an unspecified vulnerability that allows for denial of service.

CISA has added one new vulnerability to its Known Exploited Vulnerabilities (KEV) Catalog , based on evidence of active exploitation. CVE-2026-33825 Microsoft Defender Insufficient Granularity of Access Control Vulnerability This type of vulnerability is a frequent attack vector for malicious cyber actors and poses significant risks to the federal enterprise. Binding Operational Directive (BOD) 22-01: Reducing the Significant Risk of Known Exploited Vulnerabilities established the KEV Catalog as a living list of known Common Vulnerabilities and Exposures (CVEs) that carry significant risk to the federal enterprise. BOD 22-01 requires Federal Civilian Executive Branch (FCEB) agencies to remediate identified vulnerabilities by the due date to protect FCEB networks against active threats. See the BOD 22-01 Fact Sheet for more information. Although BOD 22-01 only applies to FCEB agencies, CISA strongly urges all organizations to reduce their exposure to cyberattacks by prioritizing timely remediation of KEV Catalog vulnerabilities as part of their vulnerability management practice. CISA will continue to add vulnerabilities to the catalog that meet the specified criteria . 

Microsoft Defender contains an insufficient granularity of access control vulnerability that could allow an authorized attacker to escalate privileges locally.