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Known exploited · Microsoft

CVE-2024-43573: Microsoft Windows MSHTML Platform Spoofing Vulnerability

What it is

Microsoft Windows MSHTML Platform contains an unspecified spoofing vulnerability which can lead to a loss of confidentiality.

Added October 8, 2024Due October 29, 2024CISA KEV catalog 2026.10.01

Vendor
Microsoft
Product
Windows
Added to KEV
October 8, 2024
CISA due date
October 29, 2024
Ransomware use
Unknown

What CISA requires

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Forensic triage

No

What to do now

  1. Find every instance of Windows you run, including the forgotten ones, and check its version against the vendor advisory.
  2. Apply the vendor's fix or mitigation, before October 29, 2024 if you are bound by CISA's deadline, sooner if it faces the internet.
  3. Assume it was tried against you already: look for signs of exploitation from the date it was added, not from the day you patched.
  4. Until every instance is patched, block the attack at the edge: a WAF in blocking mode stops cross-site scripting payloads.

References

CVE-2024-43573 in the National Vulnerability Database

The Dome

Block it at the edge while you patch

The Dome's WAF runs the OWASP Core Rule Set in blocking mode and stops cross-site scripting payloads before they reach your application.

See the Dome

T Academy

Train the engineers who fix it

Security engineering on real hosts in the browser, every objective checked on the machine. The first two lessons of Linux 1 are free.

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Source: CISA Known Exploited Vulnerabilities Catalog (public domain), catalog version 2026.10.01.