Out-of-bounds write
A program writes outside the memory region it is allowed to use.
CWE-787 · NVD record: nvd@nist.gov
Video course · Free course. C programming and memory concepts are useful; covers several weakness types.
Exploited. On CISA's list since 2025-03-04, and used by ransomware.
VMware ESXi Arbitrary Write Vulnerability
CVE-2025-22225 · VMware ESXi · Published 2025-03-04
How bad would it be?
8.2 out of 10
CVSS rates it high.
How likely is it to be used?
1.0%
Estimated chance of exploitation in the next 30 days, higher than 63% of all scored flaws (EPSS, 2026-10-29).
Is it already being used?
Yes
CISA has seen it exploited in real attacks. For US government agencies the fix is deadline passed 584 days ago (2025-03-25).
What CISA says to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
VMware ESXi contains an arbitrary write vulnerability. Successful exploitation allows an attacker with privileges within the VMX process to trigger an arbitrary kernel write leading to an escape of the sandbox.
What the flaw is
VMware ESXi contains an arbitrary write vulnerability. A malicious actor with privileges within the VMX process may trigger an arbitrary kernel write leading to an escape of the sandbox.
From the NVD.
Fixes and advisories
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Understand the kind of weakness behind this flaw. These resources teach the weakness, rather than reproduce this specific CVE. Follow the vendor's advice above to fix the affected product.
CWE-123 · CISA KEV; NVD record: 134c704f-9b21-4f2e-91b3-4a467353bcc0. We have not selected a close learning match for this label.
CWE is a catalogue of weakness types. Labels come from the sources shown and can differ or change. Resource matches reviewed 16 October 2026.
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Exploited flaws from CISA's KEV catalogue. Chance of exploitation from EPSS by FIRST. Descriptions and scores from the NVD. This product uses the NVD API but is not endorsed or certified by the NVD.