CVE-2026-42085

MEDIUMNVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.3 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 82% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
4.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 4.3Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

OpenC3 COSMOS provides the functionality needed to send commands to and receive data from one or more embedded systems. Prior to versions 6.10.5 and 7.0.0-rc3, OpenC3 COSMOS contains a design flaw in the save_tool_config() function that allows saving tool configuration files at arbitrary locations inside the shared /plugins directory tree by supplying crafted configuration filenames. Although the implementation sufficiently mitigates standard path traversal attacks, by canonicalizing filename to an absolute path, all plugins share this same root directory. That enables users to create arbitrary file structures and overwrite existing configuration files within the shared /plugins directory. This issue has been patched in versions 6.10.5 and 7.0.0-rc3.

CVSS v3
4.3
EG Score
4.3(medium)
EPSS
23.3%
KEV
Not listed

Published

May 4, 2026

Last Modified

May 8, 2026

Advisory Details (5)

Auto-updated May 4, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Arbitrary write to plugins directory via path-traversed config filenames · Advisory · OpenC3/cosmos · GitHub

https://github.com/OpenC3/cosmos/security/advisories/GHSA-4jvx-93h3-f45h
generic

Release v7.0.0-rc3 · OpenC3/cosmos · GitHub

https://github.com/OpenC3/cosmos/releases/tag/v7.0.0-rc3
generic

Release v6.10.5 · OpenC3/cosmos · GitHub

https://github.com/OpenC3/cosmos/releases/tag/v6.10.5
generic

Use allowlist for tool config name validation instead of denylist · OpenC3/cosmos@e6efccb · GitHub

https://github.com/OpenC3/cosmos/commit/e6efccbd148ba0e3361c5891027f2373aa140d42
generic

Prevent path traversal in tool config names · OpenC3/cosmos@9957a9f · GitHub

https://github.com/OpenC3/cosmos/commit/9957a9fa460c0c0cf5cdbf6a5931bbdd025246a5

Vendor Advisories for CVE-2026-42085(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
RubyGems(1)
PackageVulnerable rangeFixed inDependents
openc37.0.0 ... 7.1.1 (7 versions)7.0.0-rc3—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 36× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-15 16:57 UTCEPSS rescore
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  1. 2026-06-23 21:33 UTCEPSS rescore
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  12. 2026-06-15 17:49 UTCEPSS rescore
  13. 2026-06-14 08:08 UTCEG score recompute
  14. 2026-06-13 23:00 UTCEPSS rescore
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  17. 2026-06-11 14:00 UTCEPSS rescore
  18. 2026-06-11 13:44 UTCEG score recompute
  19. 2026-06-10 22:18 UTCEPSS rescore
  20. 2026-06-10 13:22 UTCEPSS rescore
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  22. 2026-06-10 13:22 UTCEG score recompute
  23. 2026-06-09 13:00 UTCEG score recompute
  24. 2026-06-08 14:17 UTCEPSS rescore
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  26. 2026-06-08 12:38 UTCEG score recompute
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  39. 2026-06-04 11:06 UTCEG score recompute
  40. 2026-06-03 10:44 UTCEG score recompute
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  42. 2026-06-01 13:52 UTCEPSS rescore
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  44. 2026-06-01 10:00 UTCEG score recompute
  45. 2026-05-31 22:30 UTCEPSS rescore
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  47. 2026-05-31 00:16 UTCEPSS rescore
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  50. 2026-05-29 13:44 UTCEPSS rescore
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  61. 2026-05-23 00:08 UTCEG score recompute
  62. 2026-05-20 22:38 UTCEPSS rescore
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  65. 2026-05-20 11:22 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2026-42085?
CVE-2026-42085 is a medium vulnerability published on May 4, 2026. OpenC3 COSMOS provides the functionality needed to send commands to and receive data from one or more embedded systems. Prior to versions 6.10.5 and 7.0.0-rc3, OpenC3 COSMOS contains a design flaw in the savetoolconfig() function that allows saving tool configuration files at arbitrary locations…
When was CVE-2026-42085 disclosed?
CVE-2026-42085 was first published in the National Vulnerability Database on May 4, 2026, with the most recent update on May 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42085 actively exploited?
CVE-2026-42085 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 23.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-42085?
CVE-2026-42085 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2026-42085?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42085, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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