How severe is CVE-2019-5544?

CVE-2019-5544 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2019-5544 being actively exploited?

Yes. CVE-2019-5544 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2021-11-03, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2019-5544?

CVE-2019-5544 primarily affects Vmware Horizon Daas. In total, 260 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-5544?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2019-5544 have an EU (EUVD) identifier?

Yes. CVE-2019-5544 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2019-15119. It is also flagged as exploited in the EUVD (since 2021-11-03).

When was CVE-2019-5544 published?

CVE-2019-5544 was published on 2019-12-06 and last updated on 2026-06-17.

CVE-2019-5544

CVE-2019-5544 is a critical-severity vulnerability in Vmware Horizon Daas with a CVSS 3.x base score of 9.8. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2021-11-03). The underlying weakness is classified as CWE-787.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 97% (100th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2021-11-03)
EU (EUVD) id: EUVD-2019-15119
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2021-11-03)
Weakness: CWE-787
Affected product: Vmware Horizon Daas
Published: 2019-12-06
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2019-5544?: 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.
How severe is CVE-2019-5544?: CVE-2019-5544 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2019-5544 being actively exploited?: Yes. CVE-2019-5544 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2021-11-03, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2019-5544?: CVE-2019-5544 primarily affects Vmware Horizon Daas. In total, 260 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-5544?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2019-5544 have an EU (EUVD) identifier?: Yes. CVE-2019-5544 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2019-15119. It is also flagged as exploited in the EUVD (since 2021-11-03).
When was CVE-2019-5544 published?: CVE-2019-5544 was published on 2019-12-06 and last updated on 2026-06-17.

References

Affected products (260)

cpe:2.3:a:vmware:horizon_daas:*:*:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:-:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:1:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:1a:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:1b:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:2:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:3:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:3a:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201504401:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201505401:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201507101:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201507102:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201507401:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201507402:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201507403:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201507404:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201507405:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201507406:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201507407:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201509101:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201509102:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201509201:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201509202:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201509203:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201509204:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201509205:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201509206:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201509207:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201509208:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201509209:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201509210:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201510401:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201511401:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201601101:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201601102:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201601401:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201601402:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201601403:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201601404:*:*:*:*:*:*
cpe:2.3:o:vmware:esxi:6.0:600-201601405:*:*:*:*:*:*

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