# What is CVE-2020-1027? > CVE-2020-1027 is a high-severity flaw (CVSS 7.8) in Windows 10 1507 from Microsoft, published on 15 April 2020. It is on the list of flaws known to be exploited, so criminals are already using it. The latest forecast puts its chance of use in the next 30 days at 4.5%. If you run an affected version, patch it first. Canonical page: https://www.precursorintelligence.com/what-is/cve-2020-1027 ## At a glance - **Verdict:** Fix this now. Attackers are using this flaw today. If you run an affected version, it goes to the top of your list. - **Precursor Intelligence risk score:** 74 out of 100 (High); action: Emergency patch. Kept up to date as the evidence changes. - **Severity:** High (CVSS 7.8 out of 10) - **Known to be exploited:** Yes, it is on the government list of flaws known to be exploited - **Chance of use in the next 30 days:** 4.5% (latest exploit-likelihood forecast) - **Published:** 15 April 2020 - **Record last updated:** 8 April 2025 - **Main product:** Windows 10 1507 from Microsoft - **Affected products:** 17 ## What is CVE-2020-1027? In plain terms An attacker has to be already on the device with an ordinary user account, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline. ### The official description An elevation of privilege vulnerability exists in the way that the Windows Kernel handles objects in memory, aka 'Windows Kernel Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2020-0913, CVE-2020-1000, CVE-2020-1003. ### What kind of flaw is it? - CWE-787: Out-of-bounds Write ### How an attack on it works - Where an attacker can be: Already on the device - How hard it is to pull off: Easy: no special conditions - Login needed first: An ordinary user account - Does someone have to click: No, nobody has to do anything - What an attacker gets: Can read data, change data and take it offline Severity vector: `CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H` ## Is CVE-2020-1027 being exploited? Yes Attackers are already using it. It is on the government list of flaws known to be exploited, and the latest forecast puts the chance of it being used in the next 30 days at 4.5%. Exploit likelihood over the last 7 days: 4.5%, 4.5%, 4.5%, 4.5%, 4.5%, 4.5%, 4.5%. ### Timeline - 15 April 2020: Published - 8 April 2025: Record last updated ### How Precursor Intelligence ranks it CVE-2020-1027 scores **74 out of 100 (High)**, with the action "Emergency patch". Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less: - Evidence it is being exploited: biggest factor - How severe it is: strong factor - How widely exposed it is: smaller factor - Threat activity around it: smaller factor 85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it. ## Who is affected by CVE-2020-1027? The published record lists 17 products. - [Windows 10 1507](https://www.precursorintelligence.com/product/microsoft/windows_10_1507) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified - [Windows 10 1607](https://www.precursorintelligence.com/product/microsoft/windows_10_1607) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified - [Windows 10 1709](https://www.precursorintelligence.com/product/microsoft/windows_10_1709) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified - [Windows 10 1803](https://www.precursorintelligence.com/product/microsoft/windows_10_1803) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified - [Windows 10 1809](https://www.precursorintelligence.com/product/microsoft/windows_10_1809) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified - [Windows 10 1903](https://www.precursorintelligence.com/product/microsoft/windows_10_1903) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified - [Windows 10 1909](https://www.precursorintelligence.com/product/microsoft/windows_10_1909) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified - [Windows 7](https://www.precursorintelligence.com/product/microsoft/windows_7) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified - [Windows 8.1](https://www.precursorintelligence.com/product/microsoft/windows_8.1) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified - [Windows Rt 8.1](https://www.precursorintelligence.com/product/microsoft/windows_rt_8.1) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified - [Windows Server 1803](https://www.precursorintelligence.com/product/microsoft/windows_server_1803) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified - [Windows Server 1903](https://www.precursorintelligence.com/product/microsoft/windows_server_1903) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified - [Windows Server 1909](https://www.precursorintelligence.com/product/microsoft/windows_server_1909) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified - [Windows Server 2008](https://www.precursorintelligence.com/product/microsoft/windows_server_2008) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): r2-sp1 - [Windows Server 2012](https://www.precursorintelligence.com/product/microsoft/windows_server_2012) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): r2 - [Windows Server 2016](https://www.precursorintelligence.com/product/microsoft/windows_server_2016) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified - [Windows Server 2019](https://www.precursorintelligence.com/product/microsoft/windows_server_2019) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified ## How do I fix CVE-2020-1027? 1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list. 2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisory first in the list. 3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in. 4. **Check it wasn’t used before you patched.** Because criminals are already using this flaw, look for signs of a break-in on affected systems using the vendor’s guidance. ### References - [portal.msrc.microsoft.com](https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1027) (Patch, Vendor advisory) - [packetstormsecurity.com](http://packetstormsecurity.com/files/168068/Windows-sxs-CNodeFactory-XMLParser_Element_doc_assembly_assemblyIdentity-Heap-Buffer-Overflow.html) (Exploit, Third-party advisory, Vulnerability database) ## Questions ### What is CVE-2020-1027? CVE-2020-1027 is a high-severity flaw in Windows 10 1507 from Microsoft, published on 15 April 2020. An attacker has to be already on the device with an ordinary user account, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline. ### How serious is CVE-2020-1027? It scores 7.8 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2020-1027 is 74 out of 100, which is High. Its action is "Emergency patch". Attackers are using this flaw today. If you run an affected version, it goes to the top of your list. ### Is CVE-2020-1027 being exploited? Attackers are already using it. It is on the government list of flaws known to be exploited, and the latest forecast puts the chance of it being used in the next 30 days at 4.5%. ### Which versions does CVE-2020-1027 affect? For Windows 10 1507 from Microsoft: version not specified. The record lists 17 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2020-1027? Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet. Because criminals are already using it, also check affected systems for signs of a break-in. ## Does CVE-2020-1027 affect you? Precursor Intelligence keeps checking for you: - **Tell us what you run.** Pick your software from a list, or let us work it out from your website. - **We match it to every flaw.** Over 400,000 published flaws, checked against your list. - **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it. - **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools. 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