CVE-2018-8420

highpriority · attend · 62EPSS 0.489 · 99 %ileexploit · PoCEURUUS

grimoire priorityP1 · Urgent

Exploitable?

Public exploit

1 exploit · PoC

Likely / severe?

48.9% (99th) EPSS

CVSS 9.3 · high

Is it mine?

57 products

Check your exposure

Who says so?

3 sources

cnnvd · enisa_euvd · fstec_bdu

EPSS · scored 2026-10-26

A remote code execution vulnerability exists when the Microsoft XML Core Services MSXML parser processes user input, aka "MS XML Remote Code Execution Vulnerability." This affects Windows 7, Windows Server 2012 R2, Windows RT 8.1, Windows Server 2008, Windows Server 2012, Windows 8.1, Windows Server 2016, Windows Server 2008 R2, Windows 10, Windows 10 Servers.

cvss

Technical severity, 0–10. One row per scoring source.

9.3

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.09.3highAV:N/AC:M/Au:N/C:C/I:C/A:Cprimary · NVD / NIST USexploitability 8.6 · impact 10

v3.08.8highCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 2.8 · impact 5.9

v3.08.8highCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:Hsecondary · CVSS-BT (t0sche)

v3.17.5highAV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-611USprimaryCWE-20US

exploits (1)

Public proof-of-concept and weaponised exploit code.

idkwim/CVE-2018-8420idkwim/CVE-2018-8420PoC · poc_in_github

affected products (57)

Products and version ranges known to be affected.

Microsoft Windows 10≤ Version 1803 for x64-based Systemsenisa_euvdEU
Microsoft Windows 10≤ Version 1803 for 32-bit Systemsenisa_euvdEU
Microsoft Windows 10≤ Version 1709 for x64-based Systemsenisa_euvdEU
Microsoft Windows 10≤ Version 1709 for 32-bit Systemsenisa_euvdEU
Microsoft Windows 10≤ Version 1607 for 32-bit Systemsenisa_euvdEU
Microsoft Windows 10≤ x64-based Systemsenisa_euvdEU
Microsoft Windows 10≤ Version 1703 for 32-bit Systemsenisa_euvdEU
Microsoft Windows 10≤ Version 1703 for x64-based Systemsenisa_euvdEU
Microsoft Windows 10≤ Version 1607 for x64-based Systemsenisa_euvdEU
Microsoft Windows 10≤ 32-bit Systemsenisa_euvdEU
Microsoft Windows 10 Servers≤ version 1803 (Server Core Installation)enisa_euvdEU
Microsoft Windows 10 Servers≤ version 1709 (Server Core Installation)enisa_euvdEU
Microsoft Windows 7≤ 32-bit Systems Service Pack 1enisa_euvdEU
Microsoft Windows 7≤ x64-based Systems Service Pack 1enisa_euvdEU
Microsoft Windows 8.1≤ 32-bit systemsenisa_euvdEU
Microsoft Windows 8.1≤ x64-based systemsenisa_euvdEU
Microsoft Windows RT 8.1≤ Windows RT 8.1enisa_euvdEU
Microsoft Windows Server 2008≤ Itanium-Based Systems Service Pack 2enisa_euvdEU
Microsoft Windows Server 2008≤ x64-based Systems Service Pack 2enisa_euvdEU
Microsoft Windows Server 2008≤ x64-based Systems Service Pack 2 (Server Core installation)enisa_euvdEU

showing 20 of 57

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu NVD CVE.org MITRE

published 2018-09-13modified 2026-06-17

related (1,520)

Related entries.

ID	severity	EPSS	exploitable	published
CVE-2025-58360US	critical9.8OT critical	61.2% (99th)	KEV	2025-11-25
GeoServer is an open source server that allows users to share and edit geospatial data. From version 2.26.0 to before 2.26.2 and before 2.25.6, an XML External Entity (XXE) vulnera…
CVE-2025-2776US	critical9.8OT critical	64.7% (99th)	KEV	2025-05-07
SysAid On-Prem versions <= 23.3.40 are vulnerable to an unauthenticated XML External Entity (XXE) vulnerability in the Server URL processing functionality, allowing for administrat…
CVE-2025-2775US	high7.5OT critical	42.6% (99th)	KEV	2025-05-07
SysAid On-Prem versions <= 23.3.40 are vulnerable to an unauthenticated XML External Entity (XXE) vulnerability in the Checkin processing functionality, allowing for administrator…
CVE-2024-34102US	—OT critical	100.0% (100th)	KEV	2024-06-13
Adobe Commerce versions 2.4.7, 2.4.6-p5, 2.4.5-p7, 2.4.4-p8 and earlier are affected by an Improper Restriction of XML External Entity Reference ('XXE') vulnerability that could re…
CVE-2023-45727US	high7.5OT critical	4.82% (92nd)	KEV	2023-10-18
Proself Enterprise/Standard Edition Ver5.62 and earlier, Proself Gateway Edition Ver1.65 and earlier, and Proself Mail Sanitize Edition Ver1.08 and earlier allow a remote unauthent…

+1515 more

references (9)

External citations — patches, advisories, analysis.

scry

Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.

Free scan