CVE-2021-21991 json
The vCenter Server contains a local privilege escalation vulnerability due to the way it handles session tokens.
published 2021-09-22 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-9162
- cvss
- 7.8
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 24%
- public exploits
- 0
- none known
Summary
The vCenter Server contains a local privilege escalation vulnerability due to the way it handles session tokens. A malicious actor with non-administrative user access on vCenter Server host may exploit this issue to escalate privileges to Administrator on the vSphere Client (HTML5) or vCenter Server vSphere Web Client (FLEX/Flash).
Patch / fix
Exploit prediction
0.32% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 4.6 | AV:L/AC:L/Au:N/C:P/I:P/A:P |
Affected products
- n/a VMware vCenter Server, VMware Cloud Foundation
Classification
- Technology feeds
References
-
vmware.com
/security/advisories/VMSA-2021-0020.html
patch, vendor-advisory
Sources
- CVE List CVE-2021-21991
- NVD CVE-2021-21991
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