CVE-2021-22919Network attack vector

Unauthenticated appliance disk exhaustion

Published Aug 5, 2021 · Updated Aug 3, 2024

Uncontrolled resource consumption in affected Citrix ADC, Gateway, and SD-WAN WANOP releases allows remote attackers to exhaust appliance disk space. Citrix has not published which management GUI request or request-processing operation consumes persistent storage without an effective limit. Exploitation requires unauthenticated network access to the management GUI, and the documented consequence is full consumption of the appliance's limited disk space.

CVSS severity7.5
High
EPSS probability0.94%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled resource consumption in affected Citrix ADC, Gateway, and SD-WAN WANOP releases allows remote attackers to exhaust appliance disk space. Citrix has not published which management GUI request or request-processing operation consumes persistent storage without an effective limit. Exploitation requires unauthenticated network access to the management GUI, and the documented consequence is full consumption of the appliance's limited disk space.

The record

CVE
CVE-2021-22919
Published
Aug 5, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-400, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 5, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.0NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

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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 exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499Endpoint Denial of Service

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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