CVE-2026-42086Public exploitNetwork attack vector

Self-XSS via array parameter eval

Published May 4, 2026 · Updated May 4, 2026

Self-XSS in OpenC3 COSMOS before 7.0.0 allows context-dependent attackers to execute JavaScript in an authenticated browser session. The CommandSender.vue convertToValue method passes user-controlled ARRAY parameter text to eval() when a command is sent. Exploitation requires an authenticated user to submit the crafted array input, such as after phishing, and exposes browser-context data and actions.

CVSS severity4.6
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Self-XSS in OpenC3 COSMOS before 7.0.0 allows context-dependent attackers to execute JavaScript in an authenticated browser session. The CommandSender.vue convertToValue method passes user-controlled ARRAY parameter text to eval() when a command is sent. Exploitation requires an authenticated user to submit the crafted array input, such as after phishing, and exposes browser-context data and actions.

The record

CVE
CVE-2026-42086
Published
May 4, 2026
Updated
May 4, 2026
Vendor
OpenC3
Product
COSMOS
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 4, 2026CVE publishedPublication date reported by the CVE source.
  2. May 4, 2026Record 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=< 7.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

OpenC3 · COSMOSversion=< 7.0.0

Published CVSS scores

4.6GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

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-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

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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