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criticalMemory Corruption

CVE-2026-47876

CVE-2026-47876 — VMXNET3 out-of-bounds write vulnerability

VMware ESX contains an out-of-bounds write vulnerability in the VMXNET3 virtual network adapter. A malicious actor with local administrative privileges on a virtual machine with VMXNET3 virtual network adapter may exploit this issue to execute code on the host. Non VMXNET3 virtual adapters are not affected by this issue.

Published Updated Sources: NVD, VMware (CNA)

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

0%

chance of exploitation in 30 days

Affects

VMware

10 products listed

CVSS base

9.3

critical

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

None

none · proof-of-concept · active

Automatable

No

can an attacker script all four kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

The vendor's own words where we have them.

Upgrade Cloud Foundation to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

  • Identify exposed assets running affected vendor/product/version combinations.
  • Prioritize based on EPSS, PoC availability, and external exposure.
  • Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

VendorProductVersionsStatus
VMwareCloud Foundation9.1.x.xVulnerable
VMwareCloud Foundation9.0.x.xVulnerable
VMwareCloud Foundation5.xVulnerable
VMwarevSphere Foundation9.1.x.xVulnerable
VMwarevSphere Foundation9.0.x.xVulnerable
VMwareESX9.1.x.xVulnerable
VMwareESX9.0.x.xVulnerable
VMwareESX8.0Vulnerable
VMwareTelco Cloud Platform5.1.xVulnerable
VMwareTelco Cloud Platform5.0.xVulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

High

Confidentiality

High

Integrity

High

Scope

Changed

Attack Complexity

Low

Attack Vector

Local

Privileges Req

None

User Interaction

None

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactSource
9.3CVSS 3.1critical2.56vmware.com (CNA), VMware (CNA)

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Weakness & attack patterns

  • CWE-787Out-of-bounds Write

Inferred from the weakness class — not observed against this CVE.

CAPEC-100 · Overflow BuffersCAPEC-123 · Buffer Manipulation

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

  1. 2026
  2. Added · CVSS 3.1 9.3 (AV:L)

    Jul 30, 2026 · NVD

  3. Initial · CVE published

    Jul 30, 2026 · NVD

References

1 on the record

Elsewhere on this site

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record1

What should defenders know first?

CVE-2026-47876 is VMXNET3 out-of-bounds write vulnerability, a critical vulnerability affecting Cloud Foundation, vSphere Foundation, ESX, Telco Cloud Platform from VMware. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-47876. Public exploit evidence is: A public PoC is not confirmed from current sources for CVE-2026-47876. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 9.3 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.