CVE-2021-31955
Published: 08 June 2021
Summary
CVE-2021-31955 is a medium-severity Exposure of Sensitive System Information to an Unauthorized Control Sphere (CWE-497) vulnerability in Microsoft Windows 10 1809. Its CVSS base score is 5.5 (Medium).
Operationally, ranked in the top 12.0% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.
The strongest mitigations our analysis identified are NIST 800-53 SC-4 (Information in Shared System Resources) and SI-16 (Memory Protection).
Deeper analysis
CVE-2021-31955 is a Windows Kernel information disclosure vulnerability, assigned CWE-497, with a CVSS 3.1 base score of 5.5 reflecting local attack vector, low complexity, and low privileges required. It affects the Windows kernel component and permits exposure of sensitive information without requiring user interaction.
A local attacker with low privileges can exploit the flaw to read kernel memory contents, achieving high confidentiality impact while leaving integrity and availability unaffected. The vulnerability can be triggered through standard local execution paths on affected Windows systems.
Microsoft has published security guidance addressing the issue via its advisory portal, and the vulnerability appears in CISA's catalog of known exploited vulnerabilities, confirming observed real-world exploitation activity.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-18828
Vulnerability details
Windows Kernel Information Disclosure Vulnerability
- CWE(s)
- KEV Date Added
- 03 November 2021
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly enforces memory protection mechanisms that block unauthorized reads of kernel memory, addressing the root cause of this information disclosure flaw.
Prevents residual kernel information from remaining accessible in shared system resources (memory) to lower-privileged processes.
Maintains separate execution domains for user processes versus kernel space, limiting the ability of local attackers to read kernel memory.