IRONSMITHINTEL
CRITICALCVSS9.8
|
Actively Exploited
|CISA KEV|CVE-2023-34048|Auth: none — unauthenticated|Reboot: required|Manual only

VMware vCenter Server Out-of-Bounds Write Vulnerability

VMware vCenter Server contains an out-of-bounds write vulnerability in the implementation of the DCERPC protocol that allows an attacker to conduct remote code execution.

Published Oct 25, 2023 · Updated May 16, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A remote attacker, without authentication, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. Federal agencies are required to remediate by 2024-02-12 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a Out-of-bounds Write (CWE-787) vulnerability in VMware vCenter Server. vCenter Server contains an out-of-bounds write vulnerability in the implementation of the DCERPC protocol. A malicious actor with network access to vCenter Server may trigger an out-of-bounds write potentially leading to remote code execution. Exploitation requires remote network access, low attack complexity, no authentication required, and no user interaction required.

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Phishing link

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Malicious file

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Server compromised

Am I affected?Quick check

Probably yes if any of these apply:

Virtualisation Administrators
Infrastructure Team
IT Security
Running vcenter server: 4.0 ≤ v ≤ 5.5, 7.0, 8.0
Real-world incidentsWhat we've seen

Active exploitation documented in the wild. Threat-research write-up: https://www.vicarius.io/vsociety/posts/understanding-cve-2023-34048-a-zero-day-out-of-bound-write-in-vcenter-server

How to patch

Manual remediation steps

Apply the Vendor Patch

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog — apply the vendor's security update as soon as possible.

CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

References

    1
    Vendor advisory: https://www.vmware.com/security/advisories/VMSA-2023-0023.html
    1
    NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2023-34048
    1
    CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-34048
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