{"id":"CVE-2019-5544","published":"2019-12-06T16:15:11Z","modified":"2026-06-17T02:37:52Z","title":"VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow Vulnerability","vendor":"VMware","product":"VMware ESXi and Horizon DaaS","tier":"core","eol":null,"description":{"text":"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.","provenance":"source","from":"NVD"},"summary":{"text":"A heap-based buffer overflow in the OpenSLP component, as used in VMware ESXi and Horizon DaaS appliances, allows a heap overwrite. An attacker with network access can exploit it without authentication or user interaction, with no special configuration required.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-29T07:10:56Z"},"cvss":{"score":9.8,"severity":"CRITICAL","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.98129,"percentile":0.99912,"date":"2026-10-28","provenance":"source"},"kev":{"dateAdded":"2021-11-03","dueDate":"2022-05-03","ransomware":true,"requiredAction":"Apply updates per vendor instructions.","notes":"https://nvd.nist.gov/vuln/detail/CVE-2019-5544","provenance":"source"},"vulncheckKev":{"dateAdded":"2020-11-11","exploitedFirstSeen":"2020-11-11","ransomware":true,"evidence":[{"url":"https://www.rapid7.com/blog/post/2020/11/11/vmware-esxi-openslp-remote-code-execution-vulnerability-cve-2020-3992-and-cve-2019-5544-what-you-need-to-know/","date":"2020-11-11"},{"url":"https://www.cyber.nj.gov/alerts-advisories/ransomware-groups-exploit-vmware-esxi-vulnerabilities","date":"2021-02-04"},{"url":"https://cybersecurityworks.com/blog/ransomware/darkside-the-ransomware-that-brought-a-us-pipeline-to-a-halt.html","date":"2021-05-18"},{"url":"https://securelist.com/it-threat-evolution-q1-2021/102382/","date":"2021-05-31"},{"url":"https://blog.qualys.com/vulnerabilities-threat-research/2021/06/09/darkside-ransomware","date":"2021-06-09"},{"url":"https://cybersecurityworks.com/blog/ransomware/darkside-ransomware-threat-associations-unearthed.html","date":"2021-06-30"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2021-11-03"},{"url":"https://blogs.juniper.net/en-us/threat-research/a-custom-python-backdoor-for-vmware-esxi-servers","date":"2022-12-09"},{"url":"https://www.crowdstrike.com/blog/hypervisor-jackpotting-lack-of-antivirus-support-opens-the-door-to-adversaries/","date":"2023-05-15"},{"url":"https://go.recordedfuture.com/hubfs/reports/cta-2024-0208.pdf","date":"2024-02-08"}],"evidenceTotal":11,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"pulses":[{"name":"Actively_Exploited_Kev 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Advisory"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DA3LYAJ2NRKMOZLZOQNDJ5TNQRFMWGHF/","tags":["Release Notes"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZPXXJZLPLAQULBCJVI5NNWZ3PGWXGXWG/","tags":["Release Notes"]},{"url":"https://security.gentoo.org/glsa/202005-12","tags":["Third Party Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-5544","tags":["US Government Resource"]}],"techniques":[{"id":"T1190","name":"Exploit Public-Facing Application","tactics":["initial-access"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: network-facing OpenSLP service exploited remotely","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"OpenSLP as used in ESXi and the Horizon DaaS 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