VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow Vulnerability

CRITICAL 9.8EXPLOITED (CISA KEV)CVE-2019-5544 · Published 06/12/2019 · updated 17/06/2026

VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow Vulnerability. Actively exploited: CISA added this vulnerability to its Known Exploited Vulnerabilities catalog on 03/11/2021. Patch affected systems as an emergency. It is known to be used in ransomware campaigns.

Package	Affected versions	Patched versions
openslp openslp	`≤ 2.0.0`	No fix yet
horizon daas vmware	`≥ 8.0.0, < 9.0.0.0`	`9.0.0.0`

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.

References

openwall.com/lists/oss-security/2019/12/10/2 · Mailing List
openwall.com/lists/oss-security/2019/12/11/2 · Mailing List
vmware.com/security/advisories/VMSA-2019-0022.html · Patch
access.redhat.com/errata/RHSA-2019:4240 · Third Party Advisory
access.redhat.com/errata/RHSA-2020:0199 · Third Party Advisory
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DA3LYAJ2NRKMOZLZOQNDJ5TNQRFMWGHF · Release Notes
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZPXXJZLPLAQULBCJVI5NNWZ3PGWXGXWG · Release Notes
security.gentoo.org/glsa/202005-12 · Third Party Advisory
cisa.gov/known-exploited-vulnerabilities-catalog · US Government Resource
CISA KEV · CVE-2019-5544

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