Micropatches Released for Windows OLE Remote Code Execution (CVE-2025-21298)

  

January 2025 Windows updates brought a fix for CVE-2025-21298, a memory corruption issue in Windows OLE data processing that can be exploited by a malicious Word document or a malicious email read in Outlook to execute arbitrary code on user's computer. (Probably also in multiple other ways, but these would be the obvious attack scenarios.)

The vulnerability was reported to Microsoft by security researchers Jmini, Rotiple, D4m0n with Trend Micro Zero Day Initiative.

Subsequently, security researcher Miloš published their analysis and POC of this vulnerability,which allowed us to reproduce the issue and create our own patches for security-adopted Windows versions that are no longer receiving updates from Microsoft.

 

Microsoft's Patch

The root cause of this issue is in function UtOlePresStmToContentsStm free'ing a stream object, but then storing the just free'd pointer which subsequently gets used again.

Microsoft patched this issue by overwriting the free's stream pointer with NULL, preventing its subsequent use.

 

Our Micropatch

Our patch does the exact same thing as Microsoft's.

Micropatch Availability

Micropatches were written for the following security-adopted versions of Windows with all available Windows Updates installed:

1. Windows 11 v21H2 - fully updated
2. Windows 10 v21H2 - fully updated
3. Windows 10 v21H1 - fully updated
4. Windows 10 v20H2 - fully updated
5. Windows 10 v2004 - fully updated
6. Windows 10 v1909 - fully updated
7. Windows 10 v1809 - fully updated
8. Windows 10 v1803 - fully updated
9. Windows 7 - fully updated without ESU, with ESU 1, ESU 2 or ESU 3
10. Windows Server 2008 R2 - - fully updated without ESU, with ESU 1, ESU 2, ESU 3 or ESU 4
11. Windows Server 2012 - fully updated without ESU, with ESU 1
12. Windows Server 2012 R2 - fully updated without ESU, with ESU 1
    

 

Micropatches have already been distributed to, and applied on, all affected online computers with 0patch Agent in PRO or Enterprise accounts (unless Enterprise group settings prevented that). 

Vulnerabilities like these get discovered on a regular basis, and attackers know about them all. If you're using Windows that aren't receiving official security updates anymore, 0patch will make sure these vulnerabilities won't be exploited on your computers - and you won't even have to know or care about these things.

If you're new to 0patch, create a free account in 0patch Central, start a free trial, then install and register 0patch Agent. Everything else will happen automatically. No computer reboot will be needed.

We would like to thank researchers Jmini, Rotiple, and D4m0n for sharing their finding with Microsoft, and security researcher Miloš for publishing their analysis and POC, which made it possible for us to create a micropatch for this issue.

Did you know 0patch will security-adopt Windows 10 when it goes out of support in October 2025, allowing you to keep using it for at least 5 more years? Read more about it here.

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