CVE-2021-22017
MediumExploitedPublic exploitRhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization.
Published Sep 22, 2021 · Updated Oct 21, 2025
Key Facts
Patch immediately- CVE-2021-22017 is a medium-severity vulnerability (CVSS 5.3 v3.1) affecting Vcenter Server (Vmware), VMware vCenter Server, VMware Cloud Foundation.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jan 10, 2022. Public exploit code is available.
- EPSS estimates a 49% probability of exploitation in the next 30 days.
- No fixed version is listed yet; check the vendor advisory for mitigations.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
5.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS (30-day exploit likelihood)
49%
Higher than 98.8% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
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Description
Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization. A malicious actor with network access to port 443 on vCenter Server may exploit this issue to bypass proxy leading to internal endpoints being accessed.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Jan 10, 2022 | Jan 24, 2022 | Not reported |
| Industry KEV feed | Jan 10, 2022 | Jan 24, 2022 | Not reported |
| CIRCL KEV | Jan 10, 2022 | Jan 24, 2022 | Not reported |
| ENISA EUVD | Jan 10, 2022 | n/a | Not reported |
Required action: Apply updates per vendor instructions.
Affected Products
2 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Vcenter ServerVmware | 6.7 | n/a |
| VMware vCenter Server, VMware Cloud Foundation | >= VMware vCenter Server(6.7 before 6.7 U3o and 6.5 before 6.5 U3q) and VMware Cloud Foundation 3.x before 3.10.2.2 | n/a |
Timeline
Publicly disclosed
Sep 22, 2021
Added to CISA KEV
Jan 10, 2022
Added to Industry KEV feed
Jan 10, 2022
Added to CIRCL KEV
Jan 10, 2022
Added to ENISA EUVD
Jan 10, 2022
Last updated
Oct 21, 2025
References
- advisoryhttp://feedproxy.google.com/
- advisoryhttps://blogs.vmware.com/vsphere/2021/09/vmsa-2021-0020-what-you-need-to-know.html
- advisoryhttps://thehackernews.com/2021/09/vmware-warns-of-critical-file-upload.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+TheHackersNews+%28The+Hackers+News+-+Cyber+Security+Blog%29
- advisoryhttps://www.bleepingcomputer.com/news/security/vmware-warns-of-critical-bug-in-default-vcenter-server-installs/
- advisoryhttps://www.itsecuritynews.info/vmware-warns-of-critical-file-upload-vulnerability-affecting-vcenter-server/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+ItSecurityNewsAggregated+%28IT+Security+News%29
FAQ
Common Questions.
Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization.
Affected: Vcenter Server (Vmware) versions 6.7; VMware vCenter Server, VMware Cloud Foundation versions >= VMware vCenter Server(6.7 before 6.7 U3o and 6.5 before 6.5 U3q) and VMware Cloud Foundation 3.x before 3.10.2.2. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Jan 10, 2022.
Yes. It was added on Jan 10, 2022 with a federal remediation due date of Jan 24, 2022.
Public exploit code is available.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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