CVE-2019-5544: VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow Vulnerability

Reference page built from the source records below, each shown as its source publishes it. Dataset version ref-8fc9b1bcdc49, updated 2026-11-02T23:39:54.475Z.

CISA Known Exploited Vulnerabilities

Name
VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow Vulnerability
Vendor
VMware
Product
VMware ESXi and Horizon DaaS
Added to the catalog
2021-11-03
Due date for US federal agencies
2022-05-03
Weaknesses
CWE-787
Catalog version
2026.10.30

VMware ESXi and Horizon Desktop as a Service (DaaS) OpenSLP contains a heap-based buffer overflow vulnerability that allows an attacker with network access to port 427 to overwrite the heap of the OpenSLP service to perform remote code execution.

Required action (CISA)

Apply updates per vendor instructions.

Ransomware use: CISA marks this vulnerability as known to be used in ransomware campaigns. CISA does not say which group used it.

Links in CISA's notes

Read on 2026-11-02T23:39:54.475Z under licence cisa-kev-cc0@b0067899 from https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

NVD analysis

Status
Analyzed
Published
2019-12-06T16:15:11.467
Last modified
2026-06-17T02:37:52.780
Weaknesses
CWE-787

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.

MetricScoreSeverityVectorScored by
CVSS 3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H[email protected] (Primary)
CVSS 3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)
CVSS 2.07.5HIGHAV:N/AC:L/Au:N/C:P/I:P/A:P[email protected] (Primary)

References

This product uses the NVD API but is not endorsed or certified by the NVD.

Read on 2026-11-02T23:41:43.468Z under licence nvd-api-terms-of-use@ff2a5288 from https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2019-5544

CVE record

Assigner
vmware
State
PUBLISHED
Published
2019-12-06T15:54:18.000Z
Updated
2025-10-21T23:35:56.590Z
Problem types
Heap Overwrite

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.

References

Read on 2026-11-03T01:02:07.482Z under licence cve-terms-of-use@81bfa2f3 from https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2019/5xxx/CVE-2019-5544.json

Defensive techniques (MITRE D3FEND)

D3FEND maps these defensive techniques to the weakness (CWE) that NVD lists for this CVE, through the digital artifacts the weakness affects. D3FEND does not say they stop this vulnerability.

CWE-787: Out-of-bounds Write

D3FEND ontology version 1.6.0.

Read on 2026-11-03T00:02:57.820Z under licence d3fend-terms-of-use@f98cbc7e from https://d3fend.mitre.org/api/weakness/cwe/CWE-787.json

MITRE D3FEND™ knowledge graph. © 2025 The MITRE Corporation.
"The MITRE Corporation (MITRE) hereby grants you a non-exclusive, royalty-free license to use D3FEND for research, development, and commercial purposes. Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." Terms: https://d3fend.mitre.org/tou/

Sources and licences

  • CISA

    Source: CISA Catalog of Known Exploited Vulnerabilities, version 2026.10.30, CC0 1.0. Use of this data does not imply endorsement by CISA or DHS.

    CC0 1.0 Universal

  • National Vulnerability Database (NIST)

    This product uses the NVD API but is not endorsed or certified by the NVD.

    NVD API Terms of Use (NIST publications in the public domain, 17 U.S.C. 105)

  • CVE Program, The MITRE Corporation

    Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation. CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.

    CVE Program Terms of Use ("CVE Usage" licence)

  • MITRE D3FEND

    MITRE D3FEND™ knowledge graph. © 2025 The MITRE Corporation.
    "The MITRE Corporation (MITRE) hereby grants you a non-exclusive, royalty-free license to use D3FEND for research, development, and commercial purposes. Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." Terms: https://d3fend.mitre.org/tou/

    MITRE D3FEND Terms of Use (site + knowledge graph); source repo MIT

Cite this page

Dragons Eye Ransomware Tracker, "CVE-2019-5544: VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow Vulnerability",
entity page, dataset version ref-8fc9b1bcdc49, updated 2026-11-02T23:39:54.475Z,
https://ransomware-tracker.com/cve/CVE-2019-5544 (accessed 2026-11-03).
Underlying source: CISA Catalog of Known Exploited Vulnerabilities, version 2026.10.30.
Underlying source: National Vulnerability Database (NIST), CVE API 2.0, record last modified 2026-06-17T02:37:52.780.
Underlying source: CVE List (CVE Program, The MITRE Corporation), record updated 2025-10-21T23:35:56.590Z.
Underlying source: MITRE D3FEND, ontology version 1.6.0.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.

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