CVE-2026-39987 (GCVE-0-2026-39987)

Vulnerability from cvelistv5 – Published: 2026-04-09 17:16 – Updated: 2026-04-24 03:55
VLAI CISA Previdian
Title
marimo Affected by Pre-Auth Remote Code Execution via Terminal WebSocket Authentication Bypass
Summary
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.
Severity
9.3 (Critical)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
SSVC
Exploitation: active Automatable: yes Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-04-23 00:00 UTC
CWE
  • CWE-306 - Missing Authentication for Critical Function
Assigner
References
Impacted products
Vendor Product Version
marimo-team marimo Affected: < 0.23.0
Create a notification for this product.
CISA
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: fccd7550-88f2-4bd1-9fad-911398288483

Vulnerability ID: CVE-2026-39987

Status: Confirmed

Status Updated: 2026-04-23 02:00 CEST

Exploited: Yes

Timestamps
First Seen: 2026-04-23
Asserted: 2026-04-23
Scope
Notes: Marimo Remote Code Execution Vulnerability | Affected: Marimo / Marimo | Description: Marimo contains an pre-authorization remote code execution vulnerability, allowing an unauthenticated attacked to shell access and execute arbitrary system commands. | Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. | Due date: 2026-05-07 | Known ransomware campaign use (KEV): Unknown | Notes (KEV): https://github.com/marimo-team/marimo/security/advisories/GHSA-2679-6mx9-h9xc ; https://nvd.nist.gov/vuln/detail/CVE-2026-39987
Evidence

Type: Vendor Report

Signal: Successful Exploitation

Confidence: 80%

Source: cisa-kev

Details
Cwes CWE-306
Feed CISA Known Exploited Vulnerabilities Catalog
Product Marimo
Due Date 2026-05-07
Date Added 2026-04-23
Vendorproject Marimo
Vulnerabilityname Marimo Remote Code Execution Vulnerability
Knownransomwarecampaignuse Unknown
References
Created: 2026-10-02 08:09 CEST | Updated: 2026-10-02 08:09 CEST
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: 4cd1433f-12ad-41a5-bbff-eb6bdd4312b3

Vulnerability ID: CVE-2026-39987

Status: Confirmed

Status Updated: 2026-06-01 15:23 CEST

Exploited: Yes

Timestamps
First Seen: 2026-06-01
Asserted: 2026-06-01
Scope
Notes: marimo Affected by Pre-Auth Remote Code Execution via Terminal WebSocket Authentication Bypass | Affected: Marimo-team / marimo | CVSS: 9.3 (CRITICAL) | EPSS: 0.37865 | Used in malware: unknown | Listed 1 day ahead of CISA KEV | Not yet in CISA KEV: False
Evidence

Type: Public Report

Signal: Successful Exploitation

Confidence: 70%

Source: previdian

Details
Feed Previdian (previdian.com)
Title marimo Affected by Pre-Auth Remote Code Execution via Terminal WebSocket Authentication Bypass
Cve Id CVE-2026-39987
Vendor Marimo-team
Ghsa Id GHSA-2679-6MX9-H9XC
Product marimo
Added Date 2026-06-01T13:23:39.702Z
Cvss Score 9.3
Epss Score 0.37865
Previous Ids
Cvss Severity CRITICAL
Virtual Patch False
Cvss Estimated False
Epss Percentile 0.98505
Used In Malware unknown
Vulnerability Id CVE-2026-39987
Ahead Of Cisa Kev 
{
  "count": 1,
  "unit": "day"
}
Not Yet In Cisa Kev False
References
Created: 2026-10-02 09:09 CEST | Updated: 2026-10-02 09:09 CEST
Show details on NVD website
To clipboard 

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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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