CVE-2021-21976Network attack vector

Authenticated remote execution via Startup Configuration injection

Published Feb 11, 2021 · Updated Aug 3, 2024

vSphere Replication 8.3.x before 8.3.1.2, 8.2.x before 8.2.1.1, 8.1.x before 8.1.2.3 and 6.5.x before 6.5.1.5 allows remote authenticated users to execute shell commands. The Startup Configuration page passes attacker-controlled input into command execution without adequate neutralization. Exploitation requires an authenticated administrator and can compromise confidentiality, integrity, and availability of the underlying appliance.

CVSS severity7.2
High
EPSS probability2.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

vSphere Replication 8.3.x before 8.3.1.2, 8.2.x before 8.2.1.1, 8.1.x before 8.1.2.3 and 6.5.x before 6.5.1.5 allows remote authenticated users to execute shell commands. The Startup Configuration page passes attacker-controlled input into command execution without adequate neutralization. Exploitation requires an authenticated administrator and can compromise confidentiality, integrity, and availability of the underlying appliance.

The record

CVE
CVE-2021-21976
Published
Feb 11, 2021
Updated
Aug 3, 2024
Vendor
VMware
Product
vSphere Replication
Classifications
CWE-78, T1059
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Feb 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=vSphere Replication 8.3.x prior to 8.3.1.2, 8.2.x prior to 8.2.1.1, 8.1.x prior to 8.1.2.3 and 6.5.x prior to 6.5.1.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

VMware · vSphere Replicationversion=vSphere Replication 8.3.x prior to 8.3.1.2, 8.2.x prior to 8.2.1.1, 8.1.x prior to 8.1.2.3 and 6.5.x prior to 6.5.1.5

Published CVSS scores

7.2NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
6.5NVDAV:N/AC:L/Au:S/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059Command and Scripting Interpreter

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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