Threats / Microsoft / CVE-2024-30040
CVE-2024-30040
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Microsoft Windows vulnerability
Microsoft Windows MSHTML Platform contains an improper input validation vulnerability enabling security feature bypass. Actively exploited in the wild.
Verdict
Today item — known-exploited.
An unspecified input validation flaw in Windows MSHTML allows attackers to circumvent security controls. The vulnerability is under active exploitation and poses immediate risk to Windows systems.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
9 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 2024-05-14).
Probability (EPSS)
EPSS 0.03939 — 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-20 Improper Input Validation.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
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 malicious input that bypasses MSHTML validation checks to trigger unintended behavior.
Business
Security controls designed to protect users are rendered ineffective, increasing exposure to downstream attacks.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I deliver the malicious payload through a vector that processes MSHTML content, such as a compromised webpage or document.
Business
User systems become vulnerable to compromise through common browsing or document-handling workflows.
3
Lateral reach — past segmentation narrative 3
Attacker
I exploit the bypassed security feature to execute arbitrary code or access restricted resources on the target system.
Business
Attackers gain unauthorized system access, enabling data theft, malware installation, or lateral movement within the network.
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