CVE-2026-39987 KEV EXPLOIT
9.8
CRITICAL · CVSS 3.1 · EPSS 37.9% (pctl 99)
Patch first
On CISA KEV — known exploited in the wild, due 2026-05-07.
Description
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.
Scoring
| CVSS | 9.8 (CRITICAL, v3.1) |
|---|---|
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| EPSS | 37.87% — more likely to be exploited than 99% of all CVEs |
| Weakness | CWE-306 |
| On CISA KEV | yes — remediate by 2026-05-07 |
| Public exploit | yes |
| Published | 2026-04-09 |
| Last modified | 2026-06-17 |
CISA KEV
| Name | Marimo Remote Code Execution Vulnerability |
|---|---|
| Added | 2026-04-23 |
| Due | 2026-05-07 |
| Vendor / product | Marimo / Marimo |
| Ransomware use | none reported |
Affected (1)
| Vendor | Product |
|---|---|
| coreweave | marimo |
Public exploits
| Source | Title | Date |
|---|---|---|
| exploit-db | Marimo 0.20.4 - RCE | 2026-09-02 |
References
- https://github.com/marimo-team/marimo/commit/c24d4806398f30be6b12acd6c60d1d7c68cfd12a
- https://github.com/marimo-team/marimo/pull/9098
- https://github.com/marimo-team/marimo/security/advisories/GHSA-2679-6mx9-h9xc
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-39987
- https://www.sysdig.com/blog/marimo-oss-python-notebook-rce-from-disclosure-to-exploitation-in-under-10-hours
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