CISA KEV catalog
Confirmed active exploitation.
Listed in CISA's catalog of Known Exploited Vulnerabilities: attackers are using it in real attacks. Patch it with priority.
- Name
- VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow Vulnerability
- Added to catalog
- Remediation due date (US federal)
- Required action
- Apply updates per vendor instructions.
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.
Affected products
vmware: horizon daas; vmware: esxi; redhat: enterprise linux desktop; redhat: enterprise linux for ibm z systems; redhat: enterprise linux for ibm z systems eus; redhat: enterprise linux for power big endian; redhat: enterprise linux for power big endian eus; redhat: enterprise linux for power little endian; redhat: enterprise linux for power little endian eus; redhat: enterprise linux server; redhat: enterprise linux server aus; redhat: enterprise linux server eus; redhat: enterprise linux server tus; redhat: enterprise linux workstation; openslp: openslp
References10
- www.vmware.com/security/advisories/VMSA-2019-0022.html PatchVendor Advisory
- www.vmware.com/security/advisories/VMSA-2019-0022.html PatchVendor Advisory
- www.openwall.com/lists/oss-security/2019/12/10/2 Mailing ListThird Party Advisory
- www.openwall.com/lists/oss-security/2019/12/11/2 Mailing ListThird Party Advisory
- 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.… Release Notes
- lists.fedoraproject.org/archives/list/package-announce%40lists.… Release Notes
- security.gentoo.org/glsa/202005-12 Third Party Advisory
- www.openwall.com/lists/oss-security/2019/12/10/2 Mailing ListThird Party Advisory
Metrics
- CVSS 3.1
-
9.8
CRITICAL
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 98% percentile: 100 · as of 10 November 2026
- CWE
- CWE-787
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.