Threats / VMware / CVE-2020-3992
CVE-2020-3992
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
VMware ESXi vulnerability
VMware ESXi OpenSLP service contains a use-after-free vulnerability allowing remote code execution from the management network via port 427.
Verdict
Today item, not a backlog item.
A use-after-free flaw in ESXi's OpenSLP implementation enables unauthenticated remote code execution for attackers with management network access. Active exploitation and ransomware deployment have been observed.
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Public proof-of-concept exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
11 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), flagged for known ransomware use.
Probability (EPSS)
EPSS 0.83015 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: VMware, ESXi. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-416 Use After Free — weakness family: Memory safety.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I identify ESXi hosts with OpenSLP listening on port 427 within the management network segment.
Business
Hypervisor inventory and network topology become visible to internal reconnaissance.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I craft a malicious OpenSLP packet that triggers the use-after-free condition in memory management.
Business
Arbitrary code execution occurs with hypervisor-level privileges.
3
Lateral reach — past segmentation narrative 3
Attacker
I establish persistent access or deploy ransomware payloads across the virtualized infrastructure.
Business
Virtual machines and critical services become encrypted or unavailable; business operations halt.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05