Actively exploited vulnerability
Microsoft Windows: security bypass flaw under attack
CVE-2024-30040 · Microsoft Windows MSHTML Platform Security Feature Bypass Vulnerability
What is affected
Microsoft Windows is found on ordinary personal computers and phones, so this is not only a problem for companies. If you use it and have not updated since the fix was released, you are exposed.
Microsoft Windows MSHTML Platform contains an unspecified vulnerability that allows for a security feature bypass.
What an attacker can do
This is a security bypass flaw. It lets an attacker slip past a built-in protection, so warnings and checks that normally stop malicious content never appear.
- How it is reached
- Over the internet or network
- Access the attacker needs
- No account needed
- Does the victim have to do something?
- Yes, the victim must open or click something
What to do
- Update Microsoft Windows now. Open the update or "About" screen, install whatever is offered and restart the app or device, because the fix is not active until you do.
- Turn on automatic updates so the next fix arrives without you having to look for it.
- If your device is too old to receive this update, stop using the affected app for anything sensitive and plan a replacement.
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Vendor advisories and fixes
- msrc.microsoft.commsrc.microsoft.com/update-guide/vulnerability/CVE-2024-30040
How urgent is it
CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on May 14, 2024, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by June 4, 2024, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.
The EPSS model estimates a 3.9% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 90% of all scored vulnerabilities.
Its CVSS severity score is 8.8 out of 10 (high), as recorded in the US National Vulnerability Database.
Technical description
Windows MSHTML Platform Security Feature Bypass Vulnerability