Threats / Microsoft / CVE-2021-31955
CVE-2021-31955
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Microsoft Windows vulnerability
Microsoft Windows Kernel information disclosure vulnerability allows attackers to read kernel memory from user-mode processes, exposing sensitive system data.
Verdict
Today item — known-exploited.
A kernel memory disclosure flaw in Windows enables unprivileged attackers to extract sensitive kernel information. Active exploitation in the wild increases risk despite low EPSS score. Patching is recommended for systems handling sensitive data.
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Public proof-of-concept exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
4 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03).
Probability (EPSS)
EPSS 0.80263 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Microsoft, Windows. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-497 CWE-497.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
WeaknessCWE-497 · CWE-497
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a user-mode process that exploits the kernel memory disclosure to read protected kernel structures.
Business
Sensitive kernel data and system secrets become accessible to attackers, undermining security isolation boundaries.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I extract kernel addresses and security tokens to bypass ASLR and other kernel protections for follow-on attacks.
Business
Attackers gain reconnaissance data needed to chain vulnerabilities into privilege escalation or persistent compromise.
3
Lateral reach — past segmentation narrative 3
Attacker
I leverage disclosed kernel memory to identify and exploit additional kernel vulnerabilities with higher impact.
Business
Information disclosure becomes a stepping stone to complete system compromise, increasing breach scope and remediation costs.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05