OpenSLP as used in ESXi and the Horizon DaaS appliances has a heap overwrite issue.
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
- Dec 6, 2019
- Updated
- Jun 16, 2026
- EPSS
- 97.3% · 100th percentile
- CWE
- CWE-787
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Report tools
Action score
98
Now
Patch today or shut off access.
- CVSS
- 39 / 40 · 9.8 / 10
- CISA KEV
- 30 / 30 · Listed
- EPSS
- 29 / 30 · 97.3%
CISA SSVC decision
- Exploitation
- active
- Automatable
- yes
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
Actively exploited in the wild
CISA added this to its Known Exploited Vulnerabilities catalog on Nov 3, 2021. That signals real attacks, not theory.
Remediation deadline for government agencies: May 3, 2022.
Known to be used in ransomware campaigns.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| openslp | openslp | cpe:2.3:a:openslp:openslp |
| vmware | horizon daas | cpe:2.3:a:vmware:horizon_daas |
| vmware | esxi | cpe:2.3:o:vmware:esxi |
| redhat | enterprise linux desktop | cpe:2.3:o:redhat:enterprise_linux_desktop |
| redhat | enterprise linux for ibm z systems | cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems |
| redhat | enterprise linux for ibm z systems eus | cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus |
| redhat | enterprise linux for power big endian | cpe:2.3:o:redhat:enterprise_linux_for_power_big_endian |
| redhat | enterprise linux for power big endian eus | cpe:2.3:o:redhat:enterprise_linux_for_power_big_endian_eus |
| redhat | enterprise linux for power little endian | cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian |
| redhat | enterprise linux for power little endian eus | cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus |
| redhat | enterprise linux server | cpe:2.3:o:redhat:enterprise_linux_server |
| redhat | enterprise linux server aus | cpe:2.3:o:redhat:enterprise_linux_server_aus |
and 4 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- fedoraproject fedora30
- fedoraproject fedora31
- openslp openslpup to 2.0.0 inclusive
- redhat enterprise linux desktop6.0
- redhat enterprise linux desktop7.0
- redhat enterprise linux for ibm z systems6.0_s390x
- redhat enterprise linux for ibm z systems7.0_s390x
- redhat enterprise linux for ibm z systems eus7.7_s390x
- redhat enterprise linux for power big endian6.0_ppc64
- redhat enterprise linux for power big endian7.0_ppc64
- redhat enterprise linux for power big endian eus7.7_ppc64
- redhat enterprise linux for power little endian7.0_ppc64le
- redhat enterprise linux for power little endian eus7.7_ppc64le
- redhat enterprise linux server6.0
- redhat enterprise linux server7.0
- redhat enterprise linux server aus7.7
- redhat enterprise linux server eus7.7
- redhat enterprise linux server tus7.7
- redhat enterprise linux workstation6.0
- redhat enterprise linux workstation7.0
Versions reported by the vendor
Affected version ranges reported by the assigning authority (vmware). Independent of NVD's CPE analysis and usually ahead of it.
n/a ESXi and Horizon DaaS
- ESXi 6.7 prior to patch release ESXi670-201912001, ESXi 6.5 prior to patch release ESXi650-201912001, ESXi 6.0 prior to patch release ESXi600-201912001 and Horizon DaaS 8.x prior to BZ-2467224-Disableaffected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:8 | openslp-dfsg | before 1.2.1-10+deb8u2 | 1.2.1-10+deb8u2 |
| Red Hat:enterprise_linux:6::client | openslp | before 1:2.0.0-4.el6_10 | 1:2.0.0-4.el6_10 |
| Red Hat:enterprise_linux:6::client | openslp-debuginfo | before 1:2.0.0-4.el6_10 | 1:2.0.0-4.el6_10 |
| Red Hat:enterprise_linux:6::client | openslp-devel | before 1:2.0.0-4.el6_10 | 1:2.0.0-4.el6_10 |
| Red Hat:enterprise_linux:6::client | openslp-server | before 1:2.0.0-4.el6_10 | 1:2.0.0-4.el6_10 |
| Red Hat:enterprise_linux:7::client | openslp | before 1:2.0.0-8.el7_7 | 1:2.0.0-8.el7_7 |
| Red Hat:enterprise_linux:7::client | openslp-debuginfo | before 1:2.0.0-8.el7_7 | 1:2.0.0-8.el7_7 |
| Red Hat:enterprise_linux:7::client | openslp-devel | before 1:2.0.0-8.el7_7 | 1:2.0.0-8.el7_7 |
| Red Hat:enterprise_linux:7::client | openslp-server | before 1:2.0.0-8.el7_7 | 1:2.0.0-8.el7_7 |
Same product
openslp: all recordsOther highest-scoring records for the same primary product.
- CVE-2016-7567Buffer overflow in the SLPFoldWhiteSpace function in common/slp_compare.c in OpenSLP 2.0 allows remote attackers to have unspecified impact 43Plan
- CVE-2017-17833OpenSLP releases in the 1.0.2 and 1.1.0 code streams have a heap-related memory corruption issue which may manifest itself as a denial-of-se40Plan
- CVE-2012-4428openslp: SLPIntersectStringList()' Function has a DoS vulnerability33Monitor
- CVE-2015-5177Double free vulnerability in the SLPDKnownDAAdd function in slpd/slpd_knownda.c in OpenSLP 1.2.1 allows remote attackers to cause a denial o32Monitor
- CVE-2016-4912The _xrealloc function in xlsp_xmalloc.c in OpenSLP 2.0.0 allows remote attackers to cause a denial of service (NULL pointer dereference and32Monitor
- CVE-2005-0769Multiple buffer overflows in OpenSLP before 1.1.5 allow remote attackers to have an unknown impact via malformed SLP packets.31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:openslp-dfsg | 1.2.1-10+deb8u2 · Debian:8 | Package registry (OSV) |
| red hat:openslp | 1:2.0.0-8.el7_7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:openslp-debuginfo | 1:2.0.0-8.el7_7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:openslp-devel | 1:2.0.0-8.el7_7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:openslp-server | 1:2.0.0-8.el7_7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
Exploit status
Weaponized
A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.
Evidence
- Nuclei detection template ×1
- Proof-of-concept repository on GitHub ×2
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Nuclei detection template | Nuclei template CVE-2019-5544 | — |
| Proof-of-concept repository on GitHub | stars:50 | 2020-12-01 |
| Proof-of-concept repository on GitHub | stars:67 | 2021-02-04 |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Published
- First PoC+360 d
- CISA KEV+697 d
- TodaySep 30, 2026+2490 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-787 · Out-of-bounds WriteCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- www.openwall.com/lists/oss-security/2019/12/10/2
- www.openwall.com/lists/oss-security/2019/12/11/2
- www.vmware.com/security/advisories/VMSA-2019-0022.html
- access.redhat.com/errata/RHSA-2019:4240
- access.redhat.com/errata/RHSA-2020:0199
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DA3LYAJ2NRKMOZLZOQNDJ5TNQRFMWGHF/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZPXXJZLPLAQULBCJVI5NNWZ3PGWXGXWG/
- security.gentoo.org/glsa/202005-12
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-5544
Vendor advisories and official records. Exploit/PoC links are deliberately left out.