Exploited CVEs / VMware / CVE-2019-5544
CVE-2019-5544
VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted, and the vulnerability is known to be used in ransomware campaigns. Federal agencies were required to remediate by 2022-05-03 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Broadcom (VMware) Security Advisories, linked below.
Actively exploited VMware ESXi and Horizon DaaS vulnerability, Critical severity, CVSS 9.8. Added to the CISA KEV catalog 2021-11-03.
Risk summary
Updated July 28, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Senserva AI Opinion for CVE-2019-5544
This heap overflow in the OpenSLP service of VMware ESXi and Horizon DaaS was a favorite entry point for ESXi-targeting ransomware crews, who used port 427 to execute code directly on hypervisors and encrypt every datastore at once. It is Critical Severity (CVSS 9.8) with a 97 percent EPSS score and confirmed ransomware use. Hypervisor compromise is the worst-case single point of failure: one exploited host can take down dozens of virtual machines.
Do this: Patch remaining ESXi hosts and disable the SLP service on any host where it is not required.
AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2019-5544
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2019-5544
Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.
CISA required action
Federal (BOD 22-01) remediation due date: 2022-05-03 (past due).
Apply updates per vendor instructions.
Official fix for CVE-2019-5544
The authoritative fix and affected-version list are published by the vendor. Find the VMware ESXi and Horizon DaaS advisory on Broadcom (VMware) Security Advisories.
Common questions about CVE-2019-5544
Is CVE-2019-5544 actively exploited?
Yes. CVE-2019-5544 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2021-11-03, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 97%. CISA also reports it is known to be used in ransomware campaigns.
What is the CISA deadline and required action for CVE-2019-5544?
CISA set the federal (BOD 22-01) remediation due date at 2022-05-03, which has passed; treat any unremediated system as overdue. The verbatim required action: Apply updates per vendor instructions.
What fixes CVE-2019-5544?
The authoritative fix is in the vendor advisory: see Broadcom (VMware) Security Advisories for the patched VMware ESXi and Horizon DaaS versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.
Can I ask my own AI about CVE-2019-5544?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2019-5544's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (5 AM and 3 PM US Central).
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Authoritative references
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