CVE tracker / CVE-2026-69789

CVE-2026-69789

CVE-2026-69789 is the Windows Reliable Multicast Transport Driver (RMCAST) Remote Code Execution Vulnerability. Microsoft rates it Critical, CVSS 7.5. It is not in CISA's Known Exploited Vulnerabilities catalog. Published October 13, 2026.

Risk summary

HighRemote Code Execution
7.5
CVSS v3 base
0.5%
EPSS: chance of exploitation in 30 days
High
Severity
Critical
Microsoft's rating
Unlikely
Microsoft: exploitation
No
In CISA KEV

Microsoft describes it: “Heap-based buffer overflow in Reliable Multicast Transport Driver (RMCAST) allows an unauthorized attacker to execute code over an adjacent network.”

How to fix it

Microsoft lists 30 affected products and the update that fixes each:

What Microsoft changed

Details

Weakness
CWE-122: Heap-based Buffer Overflow
Publicly disclosed (Microsoft)
No
Exploited (Microsoft)
No
Known exploited (CISA KEV)
Not listed
Published
October 13, 2026
Last revised
October 13, 2026

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References

Microsoft Security Update Guide NVD CVE record CWE

From Microsoft, CISA, NVD and FIRST data; the Microsoft details were read when this page was opened. Check the references above before you act.