CVE-2021-21974
OpenSLP as used in ESXi (7.0 before ESXi70U1c-17325551, 6.7 before ESXi670-202102401-SG, 6.5 before ESXi650-202102101-SG) has a heap-overflow vulnerability.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 45.1%, higher than 99% of all known CVEs. Patch or mitigate before the next change window.
Description
OpenSLP as used in ESXi (7.0 before ESXi70U1c-17325551, 6.7 before ESXi670-202102401-SG, 6.5 before ESXi650-202102101-SG) has a heap-overflow vulnerability. A malicious actor residing within the same network segment as ESXi who has access to port 427 may be able to trigger the heap-overflow issue in OpenSLP service resulting in remote code execution.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 45.06% probability · 99th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-787
- Affected
- vmware/cloud foundation · vmware/esxi
- Source
- security@vmware.com
EPSS 45.1% since 3 November 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://packetstormsecurity.com/files/162957/VMware-ESXi-OpenSLP-Heap-Overflow.htmlExploit, Third Party Advisory, VDB Entry
- https://www.vmware.com/security/advisories/VMSA-2021-0002.htmlVendor Advisory
- https://www.zerodayinitiative.com/advisories/ZDI-21-250/Third Party Advisory, VDB Entry
- http://packetstormsecurity.com/files/162957/VMware-ESXi-OpenSLP-Heap-Overflow.htmlExploit, Third Party Advisory, VDB Entry
- https://www.vmware.com/security/advisories/VMSA-2021-0002.htmlVendor Advisory
- https://www.zerodayinitiative.com/advisories/ZDI-21-250/Third Party Advisory, VDB Entry
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.