CVE-2021-42133Public exploitNetwork attack vector

Authenticated code execution via File Store relocation

Published Dec 7, 2021 · Updated Aug 4, 2024

Arbitrary file write in Ivanti Avalanche before 6.3.3 allows remote authenticated users to write files through the InfoRail Service. A SetFileStoreConfig message accepts an arbitrary local or UNC path, and Avalanche copies existing File Store contents whenever that path changes. Access to InfoRail permits an attacker-controlled SMB share to be copied into the web root, where a written JSP web shell grants code execution.

CVSS severity8.1
High
EPSS probability2.80%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Arbitrary file write in Ivanti Avalanche before 6.3.3 allows remote authenticated users to write files through the InfoRail Service. A SetFileStoreConfig message accepts an arbitrary local or UNC path, and Avalanche copies existing File Store contents whenever that path changes. Access to InfoRail permits an attacker-controlled SMB share to be copied into the web root, where a written JSP web shell grants code execution.

The record

CVE
CVE-2021-42133
Published
Dec 7, 2021
Updated
Aug 4, 2024
Vendor
Ivanti
Product
Avalanche
Classifications
CWE-434, CWE-829, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 7, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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=6.3.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Ivanti · Avalancheversion=6.3.3

Published CVSS scores

5.5NIST NVDAV:N/AC:L/Au:S/C:N/I:P/A:P
8.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/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.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
CWE-829Inclusion of Functionality from Untrusted Control Sphere
T1190Exploit Public-Facing Application

Public exploit references

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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