CVE-2021-31955
MEDIUMCISA KEVEPSS 100th pctlDescription
Windows Kernel Information Disclosure Vulnerability
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Exploit Intelligence
Very high risk: more likely to be exploited than 100% of all known CVEs.
Microsoft Windows Kernel Information Disclosure Vulnerability
Microsoft Windows Kernel contains an unspecified vulnerability that allows for information disclosure. Successful exploitation allows attackers to read the contents of kernel memory from a user-mode process.
Apply updates per vendor instructions.
Remediation due: 2021-11-17
References
Related Vulnerabilities
Other CWE-497 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2026-7864 | Medium | 6.9 | 17% | - | - |
| CVE-2025-44823 | Critical | 9.9 | 16% | - | Fix |
| CVE-2025-55131 | High | 7.1 | 3.3% | - | Fix |
| CVE-2026-34413 | High | 8.6 | 3.1% | - | - |
| CVE-2024-13999 | Critical | 9.8 | 1.8% | - | Fix |
| CVE-2024-5735 | High | 7.5 | 1.5% | - | Fix |
Common questions
How do I fix CVE-2021-31955?
Published advisories record a fix for 9 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2021-31955 being actively exploited?
Yes. CVE-2021-31955 is listed in the CISA Known Exploited Vulnerabilities catalog, which means exploitation has been observed in the wild. US federal agencies were required to remediate it by 2021-11-17. Treat it as a priority whatever its CVSS score says.
How severe is CVE-2021-31955?
CVE-2021-31955 has a CVSS v3 base score of 5.5, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2021-31955 affect?
Published advisories record a fix for Windows 10 Version 1809 (Windows), Windows 10 Version 1909 (Windows), Windows 10 Version 2004 (Windows), Windows 10 Version 20H2 (Windows), and 5 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-10-30.