CVE-2021-33742 Microsoft Windows: memory-safety flaw
In plain words: The program mishandles the memory it uses to keep track of data. A specially made input can scramble that memory. Usually lets an attacker crash the program or run their own code with its permissions.
Confirmed exploited by CISA on · US federal patch deadline Nov 17, 2021
What to do
- Install Microsoft's security update for Windows. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Let the browser auto-update and relaunch it when it asks — the fix is not active until you do.
- Keep extensions to a minimum and remove ones you do not recognise.
- Stop using Internet Explorer and any browser that no longer gets updates.
Who is affected
Could reach you. This one is aimed at devices or apps of the kind people own.
What's at risk: A malicious or hacked website can be enough. Browser bugs are often the first step in a longer attack on the whole computer or phone.
The details
- Official name
- Microsoft Windows MSHTML Platform Remote Code Execution Vulnerability
- Product
- Microsoft Windows
- CISA description
- Microsoft Windows MSHTML Platform contains an unspecified vulnerability that allows for remote code execution.
- Type of flaw
- Memory-safety flaw (CWE-787, CWE-823)
- Confirmed exploited
- Nov 3, 2021
- US federal patch deadline
- Nov 17, 2021
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Answering about CVE-2021-33742 ·
Questions about CVE-2021-33742
Is CVE-2021-33742 being exploited?
Yes. CISA added CVE-2021-33742 to its Known Exploited Vulnerabilities catalog on Nov 3, 2021, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2021-33742?
Install Microsoft's security update for Windows. If no update exists, follow the vendor's workaround or stop using the product until one ships. Let the browser auto-update and relaunch it when it asks — the fix is not active until you do.
Am I affected by CVE-2021-33742?
Only if you use Microsoft Windows. This one is aimed at devices or apps of the kind people own.