CVE-2026-42085Public exploitNetwork attack vector

Authenticated plugin configuration overwrite via traversal filenames

Published May 4, 2026 · Updated May 4, 2026

Relative path traversal in OpenC3 COSMOS before 6.10.5 and 7.0.0-rc1 through 7.0.0-rc2 allows remote authenticated users to overwrite plugin data. The save_tool_config() path canonicalization constrains writes to the shared /plugins root but fails to enforce the selected tool's configuration directory, so crafted names containing parent-directory segments reach sibling plugin paths. Access to a tool with Save Configuration is required; successful exploitation creates arbitrary directory structures and overwrites existing configuration files only within /plugins.

CVSS severity4.3
Medium
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Relative path traversal in OpenC3 COSMOS before 6.10.5 and 7.0.0-rc1 through 7.0.0-rc2 allows remote authenticated users to overwrite plugin data. The save_tool_config() path canonicalization constrains writes to the shared /plugins root but fails to enforce the selected tool's configuration directory, so crafted names containing parent-directory segments reach sibling plugin paths. Access to a tool with Save Configuration is required; successful exploitation creates arbitrary directory structures and overwrites existing configuration files only within /plugins.

The record

CVE
CVE-2026-42085
Published
May 4, 2026
Updated
May 4, 2026
Vendor
OpenC3
Product
COSMOS
Classifications
CWE-23
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=< 6.10.5
  2. Affected versionversion=>= 7.0.0.pre.rc1, < 7.0.0-rc3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

OpenC3 · COSMOSversion=< 6.10.5; version=>= 7.0.0.pre.rc1, < 7.0.0-rc3

Published CVSS scores

4.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/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-23Relative Path Traversal

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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