Cyber Resilience

CVE-2019-5544

Memory Safety in Vmware Esxi 6.0 … 6.7

CISA KEVActive ExploitationEUVD ExploitedRansomware-linkedMemory Safety
Published
06 December 2019
Modified
30 October 2025
KEV Added
03 November 2021
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.97 99.9th percentile
Risk Priority 97 floored blend · peak EPSS

Summary

CVE-2019-5544 is a critical-severity Out-of-bounds Write (CWE-787) vulnerability in Vmware Esxi. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 0.1% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

OpenSLP as used in VMware ESXi and Horizon DaaS appliances contains a heap overwrite vulnerability tracked as CVE-2019-5544. The flaw is assigned CWE-787 and carries a CVSSv3 base score of 9.8 reflecting network attack vector, low attack complexity, and no required privileges or user interaction. VMware rates the issue as critical.

An unauthenticated attacker with network access can send specially crafted SLP packets that trigger the out-of-bounds write, resulting in full compromise of confidentiality, integrity, and availability on the affected system.

Public advisories such as VMware VMSA-2019-0022 and the associated Red Hat errata RHSA-2019:4240 and RHSA-2020:0199 describe available patches and updated OpenSLP packages that remediate the flaw.

No information on observed in-the-wild exploitation is provided in the source references.

EU & UK References

Vulnerability Data

OpenSLP as used in ESXi and the Horizon DaaS appliances has a heap overwrite issue. VMware has evaluated the severity of this issue to be in the Critical severity range with a maximum CVSSv3 base score of 9.8.

CWE(s)
KEV Date Added
03 November 2021

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-37079Same product class: hypervisor / virtualizationboth on KEV
CVE-2023-34048Same product class: hypervisor / virtualizationboth on KEV
CVE-2025-22225Same product: Vmware Esxiboth on KEV
CVE-2024-38812Same product class: hypervisor / virtualizationboth on KEV
CVE-2024-22254Same product: Vmware Esxi
CVE-2023-0183Same product class: hypervisor / virtualization
CVE-2023-20895Same product class: hypervisor / virtualization
CVE-2023-20892Same product class: hypervisor / virtualization
CVE-2023-20894Same product class: hypervisor / virtualization
CVE-2024-0090Same product class: hypervisor / virtualization

Affected Assets

vmware
horizon daas
8.0.0 — 9.0.0.0
vmware
esxi
6.0, 6.5, 6.7
redhat
enterprise linux desktop
6.0, 7.0
redhat
enterprise linux for ibm z systems
6.0_s390x, 7.0_s390x
redhat
enterprise linux for ibm z systems eus
7.7_s390x
redhat
enterprise linux for power big endian
6.0_ppc64, 7.0_ppc64
redhat
enterprise linux for power big endian eus
7.7_ppc64
redhat
enterprise linux for power little endian
7.0_ppc64le
redhat
enterprise linux for power little endian eus
7.7_ppc64le
redhat
enterprise linux server
6.0, 7.0
+6 more product configuration(s) — see NVD for full list

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-787

Out-of-bounds writes that corrupt control flow or inject shellcode are rendered non-executable by the same memory protections.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure-development practices (static analysis, bounds checking, code review) are the primary means of preventing out-of-bounds writes.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover out-of-bounds write flaws so they can be remediated.

PR.PS-02 partial match
prevents

Patching or replacing vulnerable software directly eliminates known instances of this coding weakness.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing in development and acceptance can detect and prevent out-of-bounds write defects.

prevents

Secure development life cycle mandates practices that prevent out-of-bounds writes.

prevents

Application security requirements can specify bounds-checking and safe memory handling.

prevents

Secure architecture and engineering principles reduce the likelihood of buffer overflows.

prevents

Secure coding directly addresses out-of-bounds writes through language choice and coding standards.

prevents

Change management can enforce review gates that catch unsafe memory operations before deployment.

References