CVE-2019-5544

Exp

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.

Published: 2019-12-06 Last update: 2025-10-30 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2019-5544 is rated Critical Active Threat (99.3/100): CVSS Critical severity, with high exploitation likelihood (EPSS 92.48%, 100th percentile). CISA KEV confirms active exploitation (added 2021-11-03) affecting VMware / VMware ESXi and Horizon DaaS. a weakness (CWE-787) Unauthenticated remote administrative access may be possible. The CISA remediation deadline has passed—treat as an emergency patch priority.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

CISA KEV Record for CVE-2019-5544

Name: VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow Vulnerability · CISA KEV detail

Exploit added: 2021-11-03

Action due: 2022-05-03

Required action: Apply updates per vendor instructions.

Exploit prediction scoring system (EPSS) score for CVE-2019-5544

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-26 92.27% 92.48% +0.21%
2 2026-05-22 92.48% 92.27% -0.21%
3 2026-04-10 — 92.48% —

Full EPSS history (30 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2019-5544

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 134c704f-9b21-4f2e-91b3-4a467353bcc0
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2019-5544

OS Trackers for CVE-2019-5544

vendor priority summary link
gentoo normal CVE-2019-5544: 1 GLSA(s) (202005-12), 1 atom(s) (net-misc/openslp); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2019-5544
redhat critical — https://access.redhat.com/security/cve/CVE-2019-5544
suse critical CVE-2019-5544 severity critical: SUSE including 10 source package names (openslp, openslp-2.0.0-18.20.2, …), 72 product×package rows across 32 product lines (SUSE CaaS Platform 3.0, SUSE Container as a Service Platform 2.0, … (32 product lines)): Known Not Affected 63, Fixed 9. https://www.suse.com/security/cve/CVE-2019-5544/
ubuntu medium CVE-2019-5544 medium priority: Ubuntu including 1 source packages (openslp-dfsg), 8 status rows across 8 suites (bionic, disco, eoan, focal, groovy, trusty, upstream, xenial): DNE 5, released 2, needs-triage 1. https://ubuntu.com/security/CVE-2019-5544

Affected software / configurations for CVE-2019-5544

Vendor Product Version Raw CPE
vmware horizon_daas >= 8.0.0, < 9.0.0.0 cpe:2.3:a:vmware:horizon_daas:*:*:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:-:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:1:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:1a:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:1b:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:2:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:3:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:3a:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201504401:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201505401:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201507101:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201507102:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201507401:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201507402:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201507403:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201507404:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201507405:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201507406:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201507407:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201509101:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201509102:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201509201:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201509202:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201509203:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201509204:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201509205:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201509206:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201509207:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201509208:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201509209:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201509210:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201510401:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201511401:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201601101:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201601102:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201601401:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201601402:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201601403:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201601404:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201601405:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201602401:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201603101:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201603102:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201603201:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201603202:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201603203:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201603204:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201603205:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201603206:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201603207:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201603208:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201605401:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201608101:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201608401:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201608402:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201608403:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201608404:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201608405:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201610410:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201611401:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201611402:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201611403:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201702101:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201702102:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201702201:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201702202:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201702203:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201702204:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201702205:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201702206:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201702207:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201702208:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201702209:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201702210:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201702211:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201702212:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201703401:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201706101:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201706102:*:*:*:*:*:*
vmware esxi 6.0 cpe:2.3:o:vmware:esxi:6.0:600-201706103:*:*:*:*:*:*

References for CVE-2019-5544

URL Tags
http://www.openwall.com/lists/oss-security/2019/12/10/2 Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2019/12/11/2 Mailing List Third Party Advisory
http://www.vmware.com/security/advisories/VMSA-2019-0022.html Patch Vendor Advisory
https://access.redhat.com/errata/RHSA-2019:4240 Third Party Advisory
https://access.redhat.com/errata/RHSA-2020:0199 Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DA3LYAJ2NRKMOZLZOQNDJ5TNQRFMWGHF/ Release Notes
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZPXXJZLPLAQULBCJVI5NNWZ3PGWXGXWG/ Release Notes
https://security.gentoo.org/glsa/202005-12 Third Party Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-5544 US Government Resource
cvelogic Threat Intelligence