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NVD / CVE Program· CNA vmware

CVE-2021-21973: The vSphere Client (HTML5) contains an SSRF (Server Side Request Forgery) vulnerability due to improper validation of URLs in a vCenter…

MediumCVSS 5.3 · v3.1KEVWeaponized No fix recorded

Noroxi assessment

Priority: This week (action score 77/100)

  • CISA has confirmed exploitation in the wild (Mar 7, 2022). Remediation deadline for US federal agencies: Mar 21, 2022.
  • A ready-made attack module is public (Nuclei); exploiting it takes no special expertise.
  • Probability of exploitation in the next 30 days: 88% (FIRST EPSS); higher than 99.7% of all records.
  • 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.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • According to the record, no fixed version is available yet.
  • Mentioned 2 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Don’t wait for the next maintenance window. Until a fix is released, restrict access to the affected component and follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · CISA KEV · FIRST EPSS

The vSphere Client (HTML5) contains an SSRF (Server Side Request Forgery) vulnerability due to improper validation of URLs in a vCenter Server plugin. A malicious actor with network access to port 443 may exploit this issue by sending a POST request to vCenter Server plugin leading to information disclosure. This affects: VMware vCenter Server (7.x before 7.0 U1c, 6.7 before 6.7 U3l and 6.5 before 6.5 U3n) and VMware Cloud Foundation (4.x before 4.2 and 3.x before 3.10.1.2).

Published
Feb 24, 2021
Updated
Jun 16, 2026
EPSS
88.0% · 99th percentile

Report tools

JSON

Action score

77

This week

Don’t wait for the next maintenance window.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
30 / 30 · Listed
EPSS
26 / 30 · 88.0%

CISA SSVC decision

Exploitation
active
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Mar 7, 2022. That signals real attacks, not theory.

Remediation deadline for US federal agencies: Mar 21, 2022.

Get told when this record changes

  • In CISA KEV: exploitation in the wild confirmed
  • Weaponized exploit exists
  • No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-21973

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
vmwarecloud foundation
vmwarevcenter server

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 VMware Cloud Foundation

    • 4.x before 4.2, 3.x before 3.10.1.2affected

  • n/a VMware vCenter Server

    • 7.x before 7.0 U1c, 6.7 before 6.7 U3l, 6.5 before 6.5 U3naffected
Affected versions · NVD (5)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • vmware cloud foundation3.0 and later · before 3.10.1.2
  • vmware cloud foundation4.0 and later · before 4.2
  • vmware vcenter server6.5
  • vmware vcenter server6.7
  • vmware vcenter server7.0

Same product

vmware: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-22005The vCenter Server contains an arbitrary file upload vulnerability in the Analytics service.KEV
    99Now
  • CVE-2021-21972The vSphere Client (HTML5) contains a remote code execution vulnerability in a vCenter Server plugin.KEV
    99Now
  • CVE-2020-3992OpenSLP as used in VMware ESXi (7.0 before ESXi_7.0.1-0.0.16850804, 6.7 before ESXi670-202010401-SG, 6.5 before ESXi650-202010401-SG) has a…KEV
    94Now

Published before and after this one in the same product

  • ← EarlierCVE-2020-3994Oct 20, 2020 · VMware vCenter Server (6.7 before 6.7u3, 6.6 before 6.5u3k) contains a session hijack vulnerability in the vCenter Server Appliance…
    29Monitor
  • ← EarlierCVE-2020-4005Nov 20, 2020 · VMware ESXi (7.0 before ESXi70U1b-17168206, 6.7 before ESXi670-202011101-SG, 6.5 before ESXi650-202011301-SG) contains a…
    31Monitor
  • Later →CVE-2021-21974Feb 24, 2021 · OpenSLP as used in ESXi (7.0 before ESXi70U1c-17325551, 6.7 before ESXi670-202102401-SG, 6.5 before ESXi650-202102101-SG) has a…
    49Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

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 ×1

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.

Public exploit evidence
SourceKindDate
Nuclei detection templateNuclei template CVE-2021-21973 —
Proof-of-concept repository on GitHubstars:12021-03-16

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.

  1. Published
  2. First PoC+19 d
  3. CISA KEV+375 d
  4. TodayNov 14, 2026+2088 d

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

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
low · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-918 · Server-Side Request Forgery (SSRF)

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

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.

ATT&CK techniques

—

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records