Vulnerability details
CVE-2026-39987
Actively exploited
marimo-team marimo
marimo Affected by Pre-Auth Remote Code Execution via Terminal WebSocket Authentication Bypass
CVSS 4.0
9.3Critical
Official 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.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 9.3Critical | 4.0 | CVEProject cvelistV5 (CNA) (GitHub_M) | 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 |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| marimo-team | marimo | < 0.23.0 | CVEProject cvelistV5 (CNA) |
References and advisories
5- https://github.com/marimo-team/marimo/security/advisories/GHSA-2679-6mx9-h9xc x_refsource_CONFIRM
- https://github.com/marimo-team/marimo/pull/9098 x_refsource_MISC
- https://github.com/marimo-team/marimo/commit/c24d4806398f30be6b12acd6c60d1d7c68cfd12a x_refsource_MISC
- https://www.sysdig.com/blog/marimo-oss-python-notebook-rce-from-disclosure-to-exploitation-in-under-10-hours third-party-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-39987 government-resource
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Details
- Published
- 2026-04-09
- Last updated
- 2026-04-24
- State
- Published
- Assigner (CNA)
- GitHub_M
- Kolun priority
- 79 · High
CISA KEV catalog
- Date added
- 2026-04-23
- Due date
- 2026-05-07
- Used in ransomware
- Unknown
Exploit prediction (EPSS)
99.74%
Probability of exploitation in 30 days
99.9%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- Active
- Technical impact
- Total
Weaknesses (CWE)
- CWE-306Missing Authentication for Critical Function