# A denial of service vulnerability exists when Microsoft Defender improperly handles files, aka 'Microsoft Defender Denial of Service Vulnerability'. CVE record · `CVE-2019-1255` - **Identifiers:** `CVE-2019-1255` - **State:** Confirmed - **Severity:** No CVSS score - **Critical:** No - **CNA:** microsoft - **Technologies:** [Microsoft Security Essentials](https://agentprime.io/advisories/technology/microsoft-security-essentials.md) · [Microsoft System Center](https://agentprime.io/advisories/technology/microsoft-system-center.md) · [Microsoft Forefront Endpoint Protection](https://agentprime.io/advisories/technology/microsoft-forefront-endpoint-protection.md) · [Microsoft Windows Defender on Windows 7 for 32-bit Systems](https://agentprime.io/advisories/technology/microsoft-windows-defender-on-windows-7-for-32-bit-systems.md) · [Microsoft Windows Defender on Windows 7 for x64-based Systems](https://agentprime.io/advisories/technology/microsoft-windows-defender-on-windows-7-for-x64-based-systems.md) · [Microsoft Windows Defender on Windows Server 2008 R2 for x64-based Systems (Server Core installation)](https://agentprime.io/advisories/technology/microsoft-windows-defender-on-windows-server-2008-r2-for-x64-based-systems-serve.md) · [Microsoft Windows Defender on Windows Server 2008 R2 for Itanium-Based Systems](https://agentprime.io/advisories/technology/microsoft-windows-defender-on-windows-server-2008-r2-for-itanium-based-systems.md) · [Microsoft Windows Defender on Windows Server 2008 R2 for x64-based Systems](https://agentprime.io/advisories/technology/microsoft-windows-defender-on-windows-server-2008-r2-for-x64-based-systems.md) · [Microsoft Windows Defender on Windows Server 2008 for 32-bit Systems (Server Core installation)](https://agentprime.io/advisories/technology/microsoft-windows-defender-on-windows-server-2008-for-32-bit-systems-server-core.md) · [Microsoft Windows Defender on Windows Server 2012](https://agentprime.io/advisories/technology/microsoft-windows-defender-on-windows-server-2012.md) · [Microsoft Windows Defender on Windows Server 2012 (Server Core installation)](https://agentprime.io/advisories/technology/microsoft-windows-defender-on-windows-server-2012-server-core-installation.md) · [Microsoft Windows Defender on Windows 8.1 for 32-bit systems](https://agentprime.io/advisories/technology/microsoft-windows-defender-on-windows-8-1-for-32-bit-systems.md) · [Microsoft Windows Defender on Windows 8.1 for x64-based systems](https://agentprime.io/advisories/technology/microsoft-windows-defender-on-windows-8-1-for-x64-based-systems.md) · [Microsoft Windows Defender on Windows Server 2012 R2](https://agentprime.io/advisories/technology/microsoft-windows-defender-on-windows-server-2012-r2.md) · [Microsoft Windows Defender on Windows RT 8.1](https://agentprime.io/advisories/technology/microsoft-windows-defender-on-windows-rt-8-1.md) · [Microsoft Windows Defender on Windows Server 2012 R2 (Server Core installation)](https://agentprime.io/advisories/technology/microsoft-windows-defender-on-windows-server-2012-r2-server-core-installation.md) · [Microsoft Windows Defender on Windows 10 for 32-bit Systems](https://agentprime.io/advisories/technology/microsoft-windows-defender-on-windows-10-for-32-bit-systems.md) · [Microsoft Windows Defender on Windows 10 for x64-based Systems](https://agentprime.io/advisories/technology/microsoft-windows-defender-on-windows-10-for-x64-based-systems.md) · [Microsoft Windows Defender on Windows Server 2016](https://agentprime.io/advisories/technology/microsoft-windows-defender-on-windows-server-2016.md) · [Microsoft Windows Defender on Windows 10 Version 1607 for 32-bit Systems](https://agentprime.io/advisories/technology/microsoft-windows-defender-on-windows-10-version-1607-for-32-bit-systems.md) - **Published:** 23 Sept 2019 - **Updated:** 4 Aug 2024 - **Reviewed by a person:** No Published by the CVE Program (CNA: microsoft) at 23 Sept 2019, 19:14 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it. ## Affected products, as the CNA wrote them - Vendor: Microsoft. Product: Microsoft Security Essentials. - affected: `unspecified` - Vendor: Microsoft. Product: Microsoft System Center. - affected: `2012 Endpoint Protection` - affected: `Endpoint Protection` - affected: `2012 R2 Endpoint Protection` - Vendor: Microsoft. Product: Microsoft Forefront Endpoint Protection. - affected: `2010` - Vendor: Microsoft. Product: Windows Defender on Windows 7 for 32-bit Systems. - affected: `Service Pack 1` - Vendor: Microsoft. Product: Windows Defender on Windows 7 for x64-based Systems. - affected: `Service Pack 1` - Vendor: Microsoft. Product: Windows Defender on Windows Server 2008 R2 for x64-based Systems (Server Core installation). - affected: `Service Pack 1` - Vendor: Microsoft. Product: Windows Defender on Windows Server 2008 R2 for Itanium-Based Systems. - affected: `Service Pack 1` - Vendor: Microsoft. Product: Windows Defender on Windows Server 2008 R2 for x64-based Systems. - affected: `Service Pack 1` - Vendor: Microsoft. Product: Windows Defender on Windows Server 2008 for 32-bit Systems (Server Core installation). - affected: `Service Pack 2` - Vendor: Microsoft. Product: Windows Defender on Windows Server 2012. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows Server 2012 (Server Core installation). - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 8.1 for 32-bit systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 8.1 for x64-based systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows Server 2012 R2. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows RT 8.1. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows Server 2012 R2 (Server Core installation). - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 for 32-bit Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 for x64-based Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows Server 2016. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 Version 1607 for 32-bit Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 Version 1607 for x64-based Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows Server 2016 (Server Core installation). - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 Version 1703 for 32-bit Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 Version 1703 for x64-based Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 Version 1709 for 32-bit Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 Version 1709 for x64-based Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 Version 1803 for 32-bit Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 Version 1803 for x64-based Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows Server, version 1803 (Server Core Installation). - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 Version 1803 for ARM64-based Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 Version 1809 for 32-bit Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 Version 1809 for x64-based Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 Version 1809 for ARM64-based Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows Server 2019. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows Server 2019 (Server Core installation). - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 Version 1709 for ARM64-based Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 Version 1903 for 32-bit Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 Version 1903 for x64-based Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows 10 Version 1903 for ARM64-based Systems. - affected: `unspecified` - Vendor: Microsoft. Product: Windows Defender on Windows Server, version 1903 (Server Core installation). - affected: `unspecified` And 2 more products. The full list is on the CVE record: ## Not analysed yet We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter. ## Severity and exploitation No source has published a CVSS score for this record yet. - **CISA KEV:** Not listed. - **EPSS:** 0.041, the 90th percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days. ## Timeline This record came from the full history of the CVE Program, published 23 Sept 2019. New records show when each source confirmed them. ## Sources - [CVE List: CVE-2019-1255](https://www.cve.org/CVERecord?id=CVE-2019-1255) - [NVD: CVE-2019-1255](https://nvd.nist.gov/vuln/detail/CVE-2019-1255) ### References from the CNA - Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description. ## Check whether this affects you This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it. Compare the affected versions above with what you run. - With the agentprime MCP server (), `get_advisory` returns this record and `search_advisories` finds related ones. Setup: - As JSON: - Everything that needs attention now: --- The web page: . Everything for agents: .