CVE-2021-22891Known exploitationNetwork attack vector

Unauthenticated remote controller compromise

Published May 27, 2021 · Updated Aug 3, 2024

Missing authorization in Citrix ShareFile Storage Zones Controller allows remote attackers to compromise affected controllers over a network. Citrix and the CNA have not disclosed the affected request handler or the authorization check that is omitted. No account or user interaction is required; affected branches are 5.7 before 5.7.3, 5.8 before 5.8.3, 5.9 before 5.9.3, 5.10 before 5.10.1, and 5.11 before 5.11.18.

CVSS severity9.8
Critical
EPSS probability1.08%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in Citrix ShareFile Storage Zones Controller allows remote attackers to compromise affected controllers over a network. Citrix and the CNA have not disclosed the affected request handler or the authorization check that is omitted. No account or user interaction is required; affected branches are 5.7 before 5.7.3, 5.8 before 5.8.3, 5.9 before 5.9.3, 5.10 before 5.10.1, and 5.11 before 5.11.18.

The record

CVE
CVE-2021-22891
Published
May 27, 2021
Updated
Aug 3, 2024
Vendor
Citrix
Product
Citrix ShareFile Storage Zones Controller
Classifications
CWE-862, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 27, 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

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Is a vulnerable build present?

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

  1. Affected versionversion=5.7.3, 5.8.3, 5.9.3, 5.10.1, 5.11.18

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Citrix · Citrix ShareFile Storage Zones Controllerversion=5.7.3, 5.8.3, 5.9.3, 5.10.1, 5.11.18

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NVDAV:N/AC:L/Au:N/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
Privilegesunauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-862Missing Authorization
T1190Exploit Public-Facing Application

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.

Reported exploitation

Technologies

Your stack

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Your stack

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