Threats / Citrix / CVE-2021-22941
CVE-2021-22941
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-09-19
Citrix ShareFile vulnerability
Improper access control in Citrix ShareFile storage zones controller allows unauthenticated remote compromise. Actively exploited in ransomware campaigns.
Verdict
Today item, not a backlog item.
An unauthenticated attacker can bypass access controls on the storage zones controller to achieve remote code execution or unauthorized data access, enabling ransomware deployment and data exfiltration at scale.
CISA KEV Yes · 2022-03-255Ransomware use Flagged5EPSS 0.53585 (verify live)6Exploit Weaponized · public PoC7CVSS 9.8 (CISA)4CISA SSVC Exploitation: active · Automatable: yes · Impact: total4
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Fully weaponized — public exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
8 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-03-25), flagged for known ransomware use.
Probability (EPSS)
EPSS 0.53585 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) · Affected: Citrix, ShareFile. Confirm exact fixed builds in the vendor advisory.CVSS — CISA-assigned via the ADP container (CVE.org), version 3.1; the CNA left no metrics, so CISA's own score is used ahead of NVD.
Weakness (CWE)
Mapped to CWE-284 Improper Access Control — weakness family: Authorization / access control.CWE — CNA-assigned (CVE.org); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: yes · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 183 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I identify the Citrix ShareFile storage zones controller as internet-facing and lacking authentication requirements.
Business
The organization's file storage infrastructure is directly exposed to remote exploitation without credential barriers.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I exploit the access control flaw to gain unauthorized control over the storage zones controller.
Business
Attackers obtain administrative-level access to centralized file storage systems trusted by the organization.
3
Lateral reach — past segmentation narrative 3
Attacker
I deploy ransomware or data exfiltration tools across the compromised storage infrastructure.
Business
Critical business files and customer data become encrypted or stolen, triggering operational shutdown and regulatory exposure.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05
Coverage & confidence
— what we know, and what we don’tEstablished (cited)
Coverage gaps — stated, not hidden
Disclosure & credit2
Catalogued by hackeroneCNA
Credited with finding itNo finder is named in the public CVE record or the scanned vendor advisory — attribution scoped to the sources checked.
Found an error? Propose a correction.
A correction is a cited counter-claim — it must cite a source,
gets reviewed by a second human, and is never auto-applied. See the
correction convention and our identity
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