---
id: "CVE-2021-22941"
kind: "vulnerability"
aliases: ["CVE-2021-22941"]
title: "Citrix ShareFile: Citrix ShareFile Improper Access Control Vulnerability"
severity: "critical"
cvss: 10.0
epss: 0.53585
exploited: true
status: "open"
category: "vendor"
products: [{"name": "Citrix ShareFile", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "Citrix ShareFile storage zones controller", "fixed": ["5.11.20"], "affected": "< 5.11.20", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["citrix-sharefile", "exploited", "ransomware", "self-hosted", "vendor"]
not_affected_if: ["managed-hosting", "no-storage-zones-controller"]
published_at: "2021-09-23T13:15:08+00:00"
first_seen_at: "2026-10-23T19:11:52+00:00"
updated_at: "2026-10-23T21:57:35+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-22941", "first_seen_at": "2026-10-23T19:11:52+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2021-22941", "first_seen_at": "2026-10-23T19:13:44+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-10-23T21:20:29+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-22941", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

# Citrix ShareFile: Citrix ShareFile Improper Access Control Vulnerability

Improper access control (CWE-284) in self-hosted Citrix ShareFile storage zones controller before 5.11.20 lets an unauthenticated remote attacker compromise the controller. Listed in CISA KEV. Citrix-managed cloud storage zones are not affected.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Citrix ShareFile affected ? fixed ?
- vendor:Citrix ShareFile storage zones controller affected < 5.11.20 fixed 5.11.20

## How to check

Open the storage zones controller admin/config page or Windows installed programs and read the version; anything below 5.11.20 is vulnerable. Also check whether the controller is internet-facing. Citrix published no detection indicators; review IIS logs and the controller host for unexpected files or web shells.

## Fix

Upgrade ShareFile storage zones controller to 5.11.20 or later (Citrix CTX328123). Until then restrict network access to the controller.

## Timeline

- 2026-10-23T19:11:52+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-22941
- 2026-10-23T19:13:44+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2021-22941
- 2026-10-23T21:20:29+00:00 analyst — Fixed 5.11.20 per CERT-EU relaying Citrix CTX328123, CVE record, Helient. Citrix page itself unreadable (empty fetch). No public IOCs or PoC found; exploitation per CISA KEV (ransomware use per KEV flag, not verified).
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2021-22941

## Documents

- [advisory] CERT-EU 2021-050: Critical vulnerability in Citrix ShareFile (relays CTX328123) https://cert.europa.eu/publications/security-advisories/2021-050/
- [describes] CVE Record CVE-2021-22941 (references CTX328123) https://www.cve.org/CVERecord?id=CVE-2021-22941
- [fix] Helient: ShareFile SZC security update (quotes Citrix: cloud-managed zones not affected) https://www.helient.com/news/2021/09/citrix-sharefile-storage-zones-controller-security-update

## From the sources

Improper Access Control in Citrix ShareFile storage zones controller may allow an unauthenticated attacker to remotely compromise the storage zones controller.

CISA required action: Apply updates per vendor instructions.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_