CVE-2020-4020Network attack vector

Remote code execution via unsafe executable downloads

Published Jun 1, 2020 · Updated Sep 16, 2024

Remote code execution in Atlassian Companion before 1.0.0 allows remote attackers controlling its Confluence Server to run arbitrary .exe files. The file downloader fails to enforce its executable-file protection for content supplied by the connected server, permitting the downloaded .exe to launch. The gate is control of a Confluence Server already trusted by Companion, and execution occurs on the endpoint running the application.

CVSS severity7.2
High
EPSS probability1.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Remote code execution in Atlassian Companion before 1.0.0 allows remote attackers controlling its Confluence Server to run arbitrary .exe files. The file downloader fails to enforce its executable-file protection for content supplied by the connected server, permitting the downloaded .exe to launch. The gate is control of a Confluence Server already trusted by Companion, and execution occurs on the endpoint running the application.

The record

CVE
CVE-2020-4020
Published
Jun 1, 2020
Updated
Sep 16, 2024
Vendor
Atlassian
Product
Atlassian Companion
Classifications
T1105
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Jun 1, 2020CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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=unspecified <1.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Atlassian · Atlassian Companionversion=unspecified <1.0.0

Published CVSS scores

6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P
7.2NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/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.

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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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1105Ingress Tool Transfer

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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