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CISA Known Exploited Vulnerabilities

VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow Vulnerability is confirmed as actively exploited and is listed in the CISA KEV catalog.

Added to KEV
2021-11-03
Remediation due
2022-05-03
Ransomware
Known use

Required action
Apply updates per vendor instructions.

CISA notes
https://nvd.nist.gov/vuln/detail/CVE-2019-5544

Description

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.

Severity

CVSS 3.1 · CISA9.8 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC · CISA-ADP
Exploitationactive
Automatableyes
Technical impacttotal

Exploitation Context

as of October 17, 2026
All KEV statistics→
  • CISA added CVE-2019-5544 to the KEV catalog 698 days after its CVE record was published.
  • It is one of 33 VMware entries in the CISA KEV catalog, and one of 8 added in 2021.
  • Its current EPSS score (97.3%) is higher than that of 82% of CISA KEV entries.

Affected Products

ProductAffected versions
ESXi and Horizon DaaS
ESXi 6.7 prior to patch release ESXi670-201912001, ESXi 6.5 prior to patch release ESXi650-201912001, ESXi 6.0 prior to patch release ESXi600-201912001 and Horizon DaaS 8.x prior to BZ-2467224-Disable_SLPD_service_permanently_801_Hotfix.

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CVE record data © The MITRE Corporation, used under the CVE Terms of Use. Exploited-in-the-wild data from the CISA Known Exploited Vulnerabilities catalog (CC0). Exploit prediction scores by FIRST EPSS (first.org/epss). This site is not endorsed or certified by MITRE, NVD, CISA, or FIRST.