01 Record
CVE-2021-40444
Microsoft MSHTML Remote Code Execution Vulnerability
HighKEVPUBLISHEDCNA: microsoft
CNA base score8.8 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L/E:P/RL:O/RC:C
02 Description
Microsoft MSHTML Remote Code Execution Vulnerability
03 Exploitation and scoring
- Exploitation
- Exploited in the wild. Listed in the CISA Known Exploited Vulnerabilities catalog on 2021-11-03. Federal remediation due 2021-11-17. Known ransomware campaign use: reported by CISA.
- SSVC decision
- ExploitationactiveCISA reports credible evidence of active exploitation.
- AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
- Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.
- EPSS probability
- 97.84% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 99.9% of scored records. A rank, not a probability.
- NVD base score
- 8.8 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L
- NVD analysis status
- Analyzed. NVD last modified this record on 2026-08-10.
- Red Hat severity
- No Red Hat rating. Red Hat rates the CVEs that affect its products.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2021-09-15 11:24Z5 YR AGO
- Last updated
- 2026-08-10 15:10Z2 MO AGO
- Reserved
- 2021-09-02
- Assigning CNA
- microsoft
- Record state
- PUBLISHED
- Severity
- High (CVSS 8.8)
- CNA CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L/E:P/RL:O/RC:C
- Weaknesses
- CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')Base
- Data version
- 5.2
- Document digest
- 3aa6d2f0a1bdcf9550b66b3b5953b8a689a91abad0616422fcc2e0328be6cadf
05 Affected products
VendorProductVersionsPlatforms
MicrosoftWindows 10 Version 180910.0.17763.0 to < 10.0.17763.2183, 10.0.0 to < 10.0.17763.218332-bit Systems, x64-based Systems, ARM64-based Systems
MicrosoftWindows 10 Version 190910.0.0 to < 10.0.18363.180132-bit Systems, ARM64-based Systems, x64-based Systems
MicrosoftWindows 10 Version 200410.0.0 to < 10.0.19041.123732-bit Systems, ARM64-based Systems, x64-based Systems
MicrosoftWindows 10 Version 21H110.0.0 to < 10.0.19043.123732-bit Systems, ARM64-based Systems, x64-based Systems
MicrosoftWindows Server 2008 R2 Service Pack 1 (Server Core installation)6.1.7601.0 to < 6.1.7601.25712x64-based Systems
MicrosoftWindows Server 2008 Service Pack 26.0.6003.0 to < 6.0.6003.2121832-bit Systems, x64-based Systems
MicrosoftWindows Server 2008 Service Pack 2 (Server Core installation)6.0.6003.0 to < 6.0.6003.2121832-bit Systems, x64-based Systems
MicrosoftWindows Server 2012 (Server Core installation)6.2.9200.0 to < 6.2.9200.23462x64-based Systems
MicrosoftWindows Server 2012 R2 (Server Core installation)6.3.9600.0 to < 6.3.9600.20120x64-based Systems
MicrosoftWindows Server 2016 (Server Core installation)10.0.14393.0 to < 10.0.14393.4651x64-based Systems
MicrosoftWindows Server 2019 (Server Core installation)10.0.17763.0 to < 10.0.17763.2183x64-based Systems
06 References
- msrc.microsoft.comMicrosoft MSHTML Remote Code Execution Vulnerabilityhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-40444
- portal.msrc.microsoft.comhttps://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40444
- packetstormsecurity.comhttp://packetstormsecurity.com/files/164210/Microsoft-Windows-MSHTML-Overview.html
- packetstormsecurity.comhttp://packetstormsecurity.com/files/165214/Microsoft-Office-Word-MSHTML-Remote-Code-Execution.html
- packetstormsecurity.comhttp://packetstormsecurity.com/files/167317/Microsoft-Office-MSDT-Follina-Proof-Of-Concept.html
- www.cisa.govhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40444