CVE-2026-39987

CRITICALNVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score elevated to 9.8 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2026-04-23), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 9.8 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, nvd
Trending — 3 sources updated this weekExploited in the wild
9.8EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 99%CVSS: 9.8Exploit: cisa kev · ssvc active · epss top5pct · epss high · public exploitExposed: 0

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

marimo is a reactive Python notebook. Prior to 0.23.0, Marimo has a Pre-Auth RCE vulnerability. The terminal WebSocket endpoint /terminal/ws lacks authentication validation, allowing an unauthenticated attacker to obtain a full PTY shell and execute arbitrary system commands. Unlike other WebSocket endpoints (e.g., /ws) that correctly call validate_auth() for authentication, the /terminal/ws endpoint only checks the running mode and platform support before accepting connections, completely skipping authentication verification. This vulnerability is fixed in 0.23.0.

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
99(Act)
EG Risk 99/100SSVC: Act

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation100% × 40%
Automatability100% × 15%
Action: Fix now — active exploitation, automatable, high impact.
EPSS PROB
99%
EPSS %ILE
100%
KEV
⚠ Exploited

Published

April 9, 2026

Last Modified

April 23, 2026

Advisory Details (5)

Auto-updated Sep 9, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: cisa, github_commit, github_pr, github.
generic🔴 Active Exploitation

Marimo OSS Python Notebook RCE: From Disclosure to Exploitation in Under 10 Hours | Sysdig

https://www.sysdig.com/blog/marimo-oss-python-notebook-rce-from-disclosure-to-exploitation-in-under-10-hours
cisa Patch Available🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-39987
github Patch Available🟡 PoC Available

Pre-Auth Remote Code Execution via Terminal WebSocket Authentication Bypass · Advisory · marimo-team/marimo · GitHub

https://github.com/marimo-team/marimo/security/advisories/GHSA-2679-6mx9-h9xc
github_pr Patch Available

fix: properly authenticate terminal route

Patch available: marimo-team/marimo 0.23.0 (PR #9098 merged 2026-04-08)

https://github.com/marimo-team/marimo/pull/9098
github_commit Patch Available

commit c24d4806398f (marimo-team/marimo)

Patch available: marimo-team/marimo 0.23.0 (contains commit c24d4806398f)

https://github.com/marimo-team/marimo/commit/c24d4806398f30be6b12acd6c60d1d7c68cfd12a

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
marimo0.0.0 ... 0.9.9 (370 versions)0.23.0—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 31× 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.

Showing the most recent 100 of 130 total refreshes for this CVE.

  1. 2026-09-14 19:24 UTCCISA KEV update
  2. 2026-09-11 18:49 UTCCISA KEV update
  3. 2026-09-10 19:28 UTCCISA KEV update
  4. 2026-09-10 10:29 UTCEG score recompute
  5. 2026-09-10 09:34 UTCEPSS rescore
  6. 2026-09-09 19:08 UTCCISA KEV update
  7. 2026-09-08 18:54 UTCCISA KEV update
  8. 2026-09-06 15:26 UTCEG score recompute
  9. 2026-09-06 13:47 UTCEPSS rescore
  10. 2026-09-05 18:46 UTCEG score recompute
  11. 2026-09-04 17:38 UTCCISA KEV update
  12. 2026-09-04 05:30 UTCEG score recompute
  13. 2026-09-04 05:06 UTCEPSS rescore
  14. 2026-09-02 17:33 UTCCISA KEV update
  15. 2026-08-31 14:19 UTCCISA KEV update
  16. 2026-08-30 21:55 UTCEG score recompute
  17. 2026-08-30 19:17 UTCEPSS rescore
  18. 2026-08-29 00:19 UTCEG score recompute
  19. 2026-08-28 21:41 UTCEPSS rescore
  20. 2026-08-27 17:22 UTCCISA KEV update
  21. 2026-08-26 17:41 UTCCISA KEV update
  22. 2026-08-24 18:52 UTCCISA KEV update
  23. 2026-08-24 16:52 UTCEG score recompute
  24. 2026-08-24 12:44 UTCEG score recompute
  25. 2026-08-21 16:49 UTCCISA KEV update
Show 75 more
  1. 2026-08-20 17:06 UTCCISA KEV update
  2. 2026-08-19 21:10 UTCEG score recompute
  3. 2026-08-19 17:33 UTCCISA KEV update
  4. 2026-08-19 17:03 UTCEPSS rescore
  5. 2026-08-18 16:58 UTCCISA KEV update
  6. 2026-08-17 13:56 UTCCISA KEV update
  7. 2026-08-16 06:21 UTCEG score recompute
  8. 2026-08-16 02:14 UTCEPSS rescore
  9. 2026-08-12 15:37 UTCEG score recompute
  10. 2026-08-12 13:51 UTCEPSS rescore
  11. 2026-08-11 19:32 UTCCISA KEV update
  12. 2026-08-07 17:09 UTCCISA KEV update
  13. 2026-08-05 17:25 UTCCISA KEV update
  14. 2026-08-04 17:02 UTCCISA KEV update
  15. 2026-08-03 19:22 UTCCISA KEV update
  16. 2026-08-02 03:31 UTCEG score recompute
  17. 2026-08-02 02:27 UTCEPSS rescore
  18. 2026-07-30 09:19 UTCEG score recompute
  19. 2026-07-29 19:27 UTCCISA KEV update
  20. 2026-07-27 19:24 UTCCISA KEV update
  21. 2026-07-27 17:17 UTCCISA KEV update
  22. 2026-07-26 14:04 UTCEG score recompute
  23. 2026-07-26 01:38 UTCEG score recompute
  24. 2026-07-25 14:18 UTCEPSS rescore
  25. 2026-07-25 14:18 UTCEPSS rescore
  26. 2026-07-24 14:17 UTCEPSS rescore
  27. 2026-07-24 14:17 UTCEPSS rescore
  28. 2026-07-23 03:10 UTCEG score recompute
  29. 2026-07-23 00:04 UTCEG score recompute
  30. 2026-07-22 19:40 UTCCISA KEV update
  31. 2026-07-21 14:37 UTCCISA KEV update
  32. 2026-07-17 10:30 UTCEG score recompute
  33. 2026-07-16 17:04 UTCCISA KEV update
  34. 2026-07-15 16:49 UTCCISA KEV update
  35. 2026-07-15 15:04 UTCCISA KEV update
  36. 2026-07-15 02:00 UTCEPSS rescore
  37. 2026-07-14 18:05 UTCCISA KEV update
  38. 2026-07-13 17:07 UTCCISA KEV update
  39. 2026-07-10 17:52 UTCCISA KEV update
  40. 2026-07-07 19:01 UTCCISA KEV update
  41. 2026-07-07 17:16 UTCCISA KEV update
  42. 2026-07-01 19:16 UTCCISA KEV update
  43. 2026-07-01 15:06 UTCEPSS rescore
  44. 2026-06-30 23:22 UTCEPSS rescore
  45. 2026-06-29 19:12 UTCCISA KEV update
  46. 2026-06-25 19:15 UTCCISA KEV update
  47. 2026-06-25 13:49 UTCEPSS rescore
  48. 2026-06-25 13:49 UTCEPSS rescore
  49. 2026-06-23 21:33 UTCEPSS rescore
  50. 2026-06-23 17:44 UTCCISA KEV update
  51. 2026-06-18 16:13 UTCCISA KEV update
  52. 2026-06-17 17:53 UTCEPSS rescore
  53. 2026-06-16 19:33 UTCCISA KEV update
  54. 2026-06-15 19:33 UTCCISA KEV update
  55. 2026-06-15 17:49 UTCEPSS rescore
  56. 2026-06-14 23:18 UTCEPSS rescore
  57. 2026-06-12 23:12 UTCEPSS rescore
  58. 2026-06-12 23:12 UTCEPSS rescore
  59. 2026-06-12 17:35 UTCCISA KEV update
  60. 2026-06-11 19:10 UTCCISA KEV update
  61. 2026-06-10 22:18 UTCEPSS rescore
  62. 2026-06-09 18:42 UTCCISA KEV update
  63. 2026-06-09 17:12 UTCCISA KEV update
  64. 2026-06-08 19:16 UTCCISA KEV update
  65. 2026-06-08 17:26 UTCCISA KEV update
  66. 2026-06-08 14:17 UTCEPSS rescore
  67. 2026-06-08 14:17 UTCEPSS rescore
  68. 2026-06-07 15:25 UTCEPSS rescore
  69. 2026-06-07 15:25 UTCEPSS rescore
  70. 2026-06-07 15:25 UTCEPSS rescore
  71. 2026-06-06 13:47 UTCEPSS rescore
  72. 2026-06-06 13:47 UTCEPSS rescore
  73. 2026-06-05 22:47 UTCEPSS rescore
  74. 2026-06-05 22:47 UTCEPSS rescore
  75. 2026-06-05 22:43 UTCCISA KEV update

Publicly available exploits

(4 references)

Working exploit code is in the public domain (2 GitHub PoCs) (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCTh3Purge/CVE-2026-39987
    First seen Sep 8, 2026

    Marimo Pre Authentication RCE

    Open source ↗
  • Exploit-DBEDB-52673
    First seen Sep 2, 2026

    Marimo 0.20.4 - RCE

    Open source ↗
  • GitHub PoCM3PH1569/CVE-2026-39987-POC
    First seen May 24, 2026

    CVE-2026-39987 Exploitation Tool - Marimo < 0.23.0 Pre-Auth RCE (WebSocket)

    Open source ↗
  • Nucleijavascript/cves/2026/CVE-2026-39987.yaml
    First seen Jan 1, 2026

    Marimo <= 0.20.4 - Pre-Auth Terminal WebSocket RCE

    Open source ↗

Frequently asked(6)

What is CVE-2026-39987?
CVE-2026-39987 is a critical vulnerability published on April 9, 2026. marimo is a reactive Python notebook. Prior to 0.23.0, Marimo has a Pre-Auth RCE vulnerability. The terminal WebSocket endpoint /terminal/ws lacks authentication validation, allowing an unauthenticated attacker to obtain a full PTY shell and execute arbitrary system commands. Unlike other WebSocket…
When was CVE-2026-39987 disclosed?
CVE-2026-39987 was first published in the National Vulnerability Database on April 9, 2026, with the most recent update on April 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-39987 actively exploited?
Yes. CISA added CVE-2026-39987 to the Known Exploited Vulnerabilities catalog on April 23, 2026, affecting Marimo Marimo. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2026-39987?
CVE-2026-39987 has a CVSS v3 base score of 9.8 (NVD).
Which products are affected by CVE-2026-39987?
CVE-2026-39987 affects Marimo Marimo. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2026-39987?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-39987, 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.

Dependency Blast Radius

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