⚠ Known Exploited Vulnerability (KEV) Tracker

Description

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.

Lifecycle Timeline

• 2021-06-08
  CVE published

  Entered the public CVE record.

  CVE.org →
• 2021-06-08
  Vendor fix published

  Microsoft shipped a fix for Windows Kernel.

  MSRC →
• 2021-06-26
  Public exploit code 18 days later

  Public GitHub repository freeide/CVE-2021-31955-POC — unvetted, may contain malware

  GitHub PoC →
• 2021-11-03
  Added to CISA KEV 4 months later

  Listed as known exploited, which starts the federal remediation clock.

  CISA KEV →
• 2021-11-17
  Federal remediation due 14 days later

  Deadline for federal civilian agencies under BOD 22-01 — now passed.

  CISA KEV
• not recorded
  EPSS flags exploitation risk

  Reached 10% only through a model recalibration, which moves every score at once and says nothing about this CVE.
• not recorded
  First national advisory

  No tracked government advisory analyses this CVE. Routine KEV catalog-addition alerts do not count here.

Each milestone comes from a different source, so gaps between them are gaps in what those sources publish, not evidence that nothing happened. EPSS history for this CVE holds 262 points from 2021-12-11, tracked daily from 2026-09-09; earlier points are weekly, which dates a spike to within a week. Peak probability 97.4% on 2023-03-11.

Published Applicability

Check whether a specific version is affected →

What each source publishes about which product versions carry this vulnerability, kept as written rather than merged. Absence here means no source has published applicability data, not that nothing is affected.

Research & News Coverage

No mentions found in monitored research blogs or news feeds.

Detection & Exploitation

Coverage across public collections only: Nuclei and OpenVAS NVT (scan); Snort and Suricata ET Open (network); Sigma and YARA (host/SIEM); Metasploit, Exploit-DB and public GitHub repositories (exploit). Absence here means nothing public was found, not that detection is impossible.
GitHub PoC repositories are collected automatically by PoC-in-GitHub (CC0) and are not vetted: some are fakes and some are malware. Treat them as evidence that code was published, not as code to run.
OpenVAS coverage derives from the Greenbone Community Feed, made available under the Open Database License (ODbL) v1.0; its individual Vulnerability Tests are licensed GNU GPL v2.

Windows Kernel Information Disclosure Vulnerability

The vendor's own judgement about their own code, shown alongside CISA's rather than merged into it. The exploitability index is a forward-looking prediction, distinct from a CVSS severity or CISA's SSVC decision, and vendors often report observed exploitation before a CVE reaches the KEV catalog. Vendor advisory →

CISA Assessment (Vulnrichment / SSVC)

KEV Catalog Status

Listed By

Weaponization Timeline — Offensive & Testing Tools

No exploit-tool sightings recorded for this CVE.

Evidence tiers are explained on the About page — a merged Metasploit module is far stronger evidence than a distro package mention.

External References

CVE.org record → NVD entry → CISA KEV catalog → Microsoft MSRC advisory → FortiGuard Labs → Rapid7 AttackerKB →