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Fencer Vulns
critical 9.8

CVE-2019-5544 kev+ ransomware in the critical feed json

OpenSLP as used in ESXi and the Horizon DaaS appliances has a heap overwrite issue.

published 2019-12-06 6 y ago modified 2026-06-17 4 mo ago also EUVD-2019-15119

cvss
9.8
version 3.1, CNA
cisa kev
Exploited
added 2021-11-03, used in ransomware
epss
98.1%
EPSS 98.1% chance of exploitation in 30 days, percentile 99.9%
public exploits
0
none known, plus a Nuclei check

Summary

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.

Patch / fix

cisa required action Apply updates per vendor instructions.

  • vmware horizon_daas 9.0.0.0
  • openslp-dfsg Ubuntu 16.04 LTS 1.2.1-11ubuntu0.16.04.2
  • openslp-dfsg Ubuntu Pro 14.04 LTS 1.2.1-9ubuntu0.3+esm1

ubuntu advisories UBUNTU-CVE-2019-5544

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • openslp RHEL 6 1:2.0.0-4.el6_10
  • openslp-server RHEL 6 1:2.0.0-4.el6_10
  • openslp RHEL 7 1:2.0.0-8.el7_7
  • openslp-server RHEL 7 1:2.0.0-8.el7_7

red hat advisories RHSA-2020:0199RHSA-2019:4240

  • openslp CBL-Mariner 2.0, Azure Linux 3.0 2.0.0-26

azure linux advisories AZL-36968AZL-7321

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2019-5544 updated cvss 9.8

openslp: Heap-based buffer overflow in ProcessSrvRqst() in slpd_process.c leading to remote code execution

  • Red Hat Enterprise Linux Client (v. 7) openslp 2.0.0-8.el7_7, openslp-server 2.0.0-8.el7_7 Red Hat Enterprise Linux Client Optional (v. 7) openslp-devel 2.0.0-8.el7_7, openslp-debuginfo 2.0.0-8.el7_7 Red Hat Enterprise Linux ComputeNode (v. 7) openslp 2.0.0-8.el7_7, openslp-server 2.0.0-8.el7_7 Red Hat Enterprise Linux ComputeNode Optional (v. 7) openslp-devel 2.0.0-8.el7_7, openslp-debuginfo 2.0.0-8.el7_7
    fixed: vendor fix “There is no known mitigation.” RHSA-2019:4240
  • Red Hat Enterprise Linux Desktop (v. 6) openslp 2.0.0-4.el6_10 Red Hat Enterprise Linux Desktop Optional (v. 6) openslp-server 2.0.0-4.el6_10 Red Hat Enterprise Linux HPC Node (v. 6) openslp 2.0.0-4.el6_10 Red Hat Enterprise Linux HPC Node Optional (v. 6) openslp-server 2.0.0-4.el6_10 Red Hat Enterprise Linux Server (v. 6) openslp 2.0.0-4.el6_10
    fixed: vendor fix “There is no known mitigation.” RHSA-2020:0199
  • Red Hat Enterprise Linux Server (v. 7) openslp 2.0.0-8.el7_7, openslp-server 2.0.0-8.el7_7
    fixed: vendor fix “There is no known mitigation.” RHSA-2019:4240
  • Red Hat Enterprise Linux Server Optional (v. 6) openslp-server 2.0.0-4.el6_10
    fixed: vendor fix “There is no known mitigation.” RHSA-2020:0199
  • Red Hat Enterprise Linux Server Optional (v. 7) openslp-devel 2.0.0-8.el7_7, openslp-debuginfo 2.0.0-8.el7_7
    fixed: vendor fix “There is no known mitigation.” RHSA-2019:4240
  • Red Hat Enterprise Linux Workstation (v. 6) openslp 2.0.0-4.el6_10
    fixed: vendor fix “There is no known mitigation.” RHSA-2020:0199
  • Red Hat Enterprise Linux Workstation (v. 7) openslp 2.0.0-8.el7_7, openslp-server 2.0.0-8.el7_7
    fixed: vendor fix “There is no known mitigation.” RHSA-2019:4240
  • Red Hat Enterprise Linux Workstation Optional (v. 6) openslp-server 2.0.0-4.el6_10
    fixed: vendor fix “There is no known mitigation.” RHSA-2020:0199
show 2 more
  • Red Hat Enterprise Linux Workstation Optional (v. 7) openslp-devel 2.0.0-8.el7_7, openslp-debuginfo 2.0.0-8.el7_7
    fixed: vendor fix “There is no known mitigation.” RHSA-2019:4240
  • Red Hat Enterprise Linux 8 openslp Red Hat Enterprise Linux 9 openslp, openslp-server
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Timeline

  1. Published
  2. Added to CISA KEV
  3. CISA patch deadline
  4. CISA SSVC: exploitation active

Known exploited

Added
5 y ago
Patch by
2022-05-03 (4 y ago)
Ransomware
Known to be used in ransomware campaigns
Required action
Apply updates per vendor instructions.
Vendor, product
VMware, VMware ESXi and Horizon DaaS
CISA name
VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow Vulnerability

CISA SSVC

Exploitation
Active, exploited in the wild
Automatable
yes
Technical impact
total
Assessed
21 mo ago

Exploit prediction

98.13% chance of exploitation in the next 30 days, higher than 99.9% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • n/a ESXi and Horizon DaaS

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.