CVE-2026-39987
Actively exploited. CVE-2026-39987 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-04-23) — exploitation has been observed in the wild, and US federal agencies are required to remediate it under BOD 22-01. Treat patching as urgent.
Public exploit code is available. Proof-of-concept or working exploit code for CVE-2026-39987 is indexed in GitHub PoC and Nuclei. Expect opportunistic scanning and exploitation attempts — prioritize remediation.
Marimo contains an pre-authorization remote code execution vulnerability, allowing an unauthenticated attacked to shell access and execute arbitrary system commands.
CSIRTS triage
- What
- The vulnerability allows an unauthenticated attacker to gain shell access and execute arbitrary system commands.
- Who is affected
- Users of Marimo are affected.
- Urgency
- Remediation is urgent due to the critical nature of the vulnerability and its exploitation status.
- Action
- Apply the available patch immediately.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Exploitation confirmedAlready exploited in the wild (CISA KEV) — the prediction phase is over. Patch now. Riskier than 100% of all EPSS-scored CVEs.
Exploit availability
Public exploit or proof-of-concept code for CVE-2026-39987 is indexed in these free datasets. Available exploit code raises real-world risk independent of the CVSS score.
- GitHub PoCPublic proof-of-concept repositories on GitHub reference this CVE.look it up ↗
- NucleiA nuclei-templates detection/PoC template exists for this CVE.look it up ↗
Advisory coverage (1)
- criticalexploitedCVE-2026-39987: Marimo Remote Code Execution Vulnerabilitycisa-kev · 2026-04-23
External references
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[](https://www.csirts.com/cve/CVE-2026-39987)