CVE-2026-77602

CRITICALPre-NVD 9.99.9
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 9.9 from GitHub Security Advisory (severity: CRITICAL) published 2026-09-23. A secondary CVSS source baseline 9.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this weekElevated

Also known asEUVD-2026-85566 (ENISA EUVD) · GHSA-jjq7-m736-w977 (GitHub Security Advisories)Source: ENISA EUVD

9.9EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 9.9Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

OpenC3 COSMOS provides the functionality needed to send commands to and receive data from one or more embedded systems. From 5.1.0 until 7.3.0, authenticated non-administrator users can write content under targets_modified/ that is later executed by multiple configuration paths below the intended code-execution privilege tier. Table and command or telemetry definitions are processed through ConfigParser, PacketConfig, GENERIC_READ_CONVERSION, or GENERIC_WRITE_CONVERSION, allowing ERB rendering or Ruby and Python evaluation, while openc3-cosmos-script-runner-api/scripts/run_suite_analysis.rb executes suite procedure files through require. Storage uploads, screen saves, and script creation can place content in the overlay, and triggering table processing, a cmd/tlm reload, or suite analysis executes the content in cmd-tlm-api, decom microservices, or Script Runner with access to internal credentials and data. This issue is fixed in version 7.3.0.

CVSS v3
9.9
EG Score
9.9CRITICALmedium confidence
EG Risk
61
EG Risk 61/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity99% × 45%
Impact severity (EG Severity): CVSS 9.9 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.7%
EPSS %ILE
53rd
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (9.9): severity, escalated by confirmed exploitation. This CVE's 9.9 is its impact severity (EG Severity), not escalated.

EG Severity
9.9 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.7% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track* at medium mission impactTrack at low, Track* at medium and Attend at high mission impact.CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low, Track* at medium and Attend at high mission impact.

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

September 23, 2026

Last Modified

September 29, 2026

Advisory Details (4)

Auto-updated Oct 27, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_pr, github.
GitHub advisoryMentions a patch (unverified)🟡 PoC Available

Authenticated remote code execution via the user-writable config overlay (table definitions, cmd/tlm definitions, and script suites) · Advisory · OpenC3/cosmos · GitHub

https://github.com/OpenC3/cosmos/security/advisories/GHSA-jjq7-m736-w977
GitHub pull request

Treat targets_modified overlay as data, not code

Fix merged in OpenC3/cosmos PR #3488 on 2026-07-02 — awaiting tagged release

https://github.com/OpenC3/cosmos/pull/3488
GitHub commit

commit 7a1538a4626f (OpenC3/cosmos)

Fix landed in OpenC3/cosmos commit 7a1538a4626f — awaiting tagged release

https://github.com/OpenC3/cosmos/commit/7a1538a4626f82c0d1540fcaa27ffdcbbd71ff81
GitHub commit

commit 71943352a281 (OpenC3/cosmos)

Fix landed in OpenC3/cosmos commit 71943352a281 — awaiting tagged release

https://github.com/OpenC3/cosmos/commit/71943352a28128ef3e7e894319d97a656b5cd4f2

Vendor Advisories for CVE-2026-77602(1)

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

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
rubygemsopenc3 @ 7.3.0 (fixes >= 5.1.0, <= 7.2.1)—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
RubyGems(1)
PackageVulnerable rangeFix by version rangeDependents
openc35.1.0 ... 7.2.1 (78 versions)
  • 5.1.0 up to 7.3.0: fixed in 7.3.0
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 15× in last 7d / 66× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  2. 2026-11-01 13:13 UTCGHSA enrichmentGHSA-jjq7-m736-w977 · GitHub severity CRITICAL · GitHub CVSS 9.9
  3. 2026-11-01 07:38 UTCGHSA enrichmentGHSA-jjq7-m736-w977 · GitHub severity CRITICAL · GitHub CVSS 9.9
  4. 2026-11-01 07:38 UTCEG score recompute
  5. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  6. 2026-10-31 12:54 UTCEG score recompute
  7. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  8. 2026-10-30 12:36 UTCEG score recompute
  9. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  10. 2026-10-29 12:16 UTCEG score recompute
  11. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  12. 2026-10-28 11:50 UTCEG score recompute
  13. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  14. 2026-10-27 11:27 UTCEG score recompute
  15. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  16. 2026-10-26 11:09 UTCEG score recompute
  17. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  18. 2026-10-25 14:01 UTCEG score recompute
  19. 2026-10-25 10:52 UTCEG score recompute
  20. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  21. 2026-10-24 10:34 UTCEG score recompute
  22. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  23. 2026-10-23 10:13 UTCEG score recompute
  24. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  25. 2026-10-22 09:49 UTCEG score recompute
Show 63 more
  1. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  2. 2026-10-21 09:29 UTCEG score recompute
  3. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  4. 2026-10-20 09:12 UTCEG score recompute
  5. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  6. 2026-10-19 08:52 UTCEG score recompute
  7. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  8. 2026-10-18 03:11 UTCEG score recompute
  9. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  10. 2026-10-17 07:32 UTCEG score recompute
  11. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  12. 2026-10-16 07:12 UTCEG score recompute
  13. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  14. 2026-10-15 06:01 UTCEG score recompute
  15. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  16. 2026-10-14 01:39 UTCEG score recompute
  17. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  18. 2026-10-12 21:50 UTCEG score recompute
  19. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  20. 2026-10-12 15:37 UTCEG score recompute
  21. 2026-10-11 19:23 UTCEG score recompute
  22. 2026-10-11 16:39 UTCEG score recompute
  23. 2026-10-11 13:57 UTCEG score recompute
  24. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  25. 2026-10-11 11:46 UTCEG score recompute
  26. 2026-10-10 20:03 UTCEG score recompute
  27. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  28. 2026-10-09 20:35 UTCEG score recompute
  29. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  30. 2026-10-08 21:03 UTCEG score recompute
  31. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  32. 2026-10-08 02:05 UTCEG score recompute
  33. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  34. 2026-10-06 18:41 UTCEG score recompute
  35. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  36. 2026-10-05 18:51 UTCEG score recompute
  37. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  38. 2026-10-05 03:04 UTCEG score recompute
  39. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  40. 2026-10-03 15:50 UTCEG score recompute
  41. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  42. 2026-10-02 19:39 UTCEG score recompute
  43. 2026-10-01 19:58 UTCEG score recompute
  44. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  45. 2026-09-30 16:38 UTCEG score recompute
  46. 2026-09-29 19:13 UTCEG score recompute
  47. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  48. 2026-09-29 03:33 UTCEG score recompute
  49. 2026-09-29 02:36 UTCEG score recompute
  50. 2026-09-28 22:11 UTCEG score recompute
  51. 2026-09-28 18:14 UTCEG score recompute
  52. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  53. 2026-09-27 14:21 UTCEG score recompute
  54. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  55. 2026-09-26 18:39 UTCEG score recompute
  56. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  57. 2026-09-26 03:02 UTCEG score recompute
  58. 2026-09-26 00:28 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  59. 2026-09-24 15:03 UTCEG score recompute
  60. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  61. 2026-09-23 19:26 UTCEG score recompute
  62. 2026-09-23 19:04 UTCEG score recomputeFirst assessed: 9.9 CRITICAL
  63. 2026-09-23 19:04 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-77602?
CVE-2026-77602 is a critical-severity vulnerability; its CVE record was published on September 23, 2026. OpenC3 COSMOS provides the functionality needed to send commands to and receive data from one or more embedded systems. From 5.1.0 until 7.3.0, authenticated non-administrator users can write content under targets_modified/ that is later executed by multiple configuration paths below the intended…
When was the CVE record for CVE-2026-77602 published?
The CVE record for CVE-2026-77602 was published on September 23, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 29, 2026; the record at its source may have been updated since.
Is CVE-2026-77602 actively exploited?
CVE-2026-77602 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (53rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-77602?
CVE-2026-77602 has a CVSS base score of 9.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-77602?
A fix for CVE-2026-77602 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-77602 are linked in the Vendor Advisories panel on this page.

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