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Human Attacker Hits Machine-Speed Exploitation of Marimo RCE

Part of the CVE-2026-39987 story · since 10 Apr

Quiet for 6 weekslast report 14 Sep8 articles5 outlets
10 Apr · SecurityWeek first22 Jul26 AugNowThis article8th of 8
  • Fri 10 Apr, 09:41 UTC. SecurityWeek, first report. Attackers exploit Marimo CVE-2026-39987 flaw hours after advisory. Cites a CVE in CISA KEV.
  • Fri 10 Apr, 11:26 UTC. The Hacker News, its first report on the story. Marimo flaw lets attackers gain shell within hours of disclosure. Cites a CVE in CISA KEV.
  • Sat 11 Apr, 10:21 UTC. Security Affairs, its first report on the story. CVE-2026-39987: Marimo RCE exploited in hours after disclosure. Cites a CVE in CISA KEV.
  • Sun 12 Apr, 09:21 UTC. Security Affairs. Security Affairs newsletter Round 572 by Pierluigi Paganini – INTERNATIONAL EDITION. Cites a CVE in CISA KEV.
  • Thu 23 Apr, 18:33 UTC. CISA, its first report on the story. CISA Flags Critical Marimo RCE Bug CVE-2026-39987 in KEV. Cites a CVE in CISA KEV.
  • Thu 23 Apr, 19:11 UTC. CISA. CISA Flags Marimo RCE Flaw in KEV, Urges Immediate Patching Action. Cites a CVE in CISA KEV.
  • Fri 29 May, 16:05 UTC. The Hacker News. Attackers Deploy AI LLM Agent After Marimo CVE-2026-39987 Breach. Cites a CVE in CISA KEV.
  • Mon 14 Sep, 14:51 UTC. Infosecurity, its first report on the story. Human Attacker Hits Machine-Speed Exploitation of Marimo RCE. Cites a CVE in CISA KEV. This article, 8th of 8.

A human attacker successfully exploited a remote code execution flaw (CVE-2026-39987) in Marimo notebooks, moving from a vulnerable device to an SSH bastion host in just eight seconds. This speed, typically attributed to AI, was achieved with a hand-crafted toolkit. The attacker harvested cloud credentials from the notebook and executed commands over a nine-hour period, highlighting that human and AI attacks can look different while targeting the same vulnerabilities.

Recommendations include updating the software, improving authentication on the terminal endpoint, and managing permissions carefully. This flaw is listed in CISA's Known Exploited Vulnerabilities catalog, with remediation deadlines approaching.

How the story developed

All 8 articles
Quiet for 6 weekslast report 14 Sep8 articles5 outlets

8 articles from 5 outlets since 10 Apr. Quiet since 14 Sep. This was the 8th report, 157 days after the first.

Now10 Apr2127261116222813 SepFirst reportSecurityWeek · 10 Apr, 09:41This article8th of 8 · day 157CISA alert23 Apr, 18:33 · official
  • Fri 10 Apr, 09:41 UTC. SecurityWeek, first report. Attackers exploit Marimo CVE-2026-39987 flaw hours after advisory. Cites a CVE in CISA KEV.
  • Fri 10 Apr, 11:26 UTC. The Hacker News, its first report on the story. Marimo flaw lets attackers gain shell within hours of disclosure. Cites a CVE in CISA KEV.
  • Sat 11 Apr, 10:21 UTC. Security Affairs, its first report on the story. CVE-2026-39987: Marimo RCE exploited in hours after disclosure. Cites a CVE in CISA KEV.
  • Sun 12 Apr, 09:21 UTC. Security Affairs. Security Affairs newsletter Round 572 by Pierluigi Paganini – INTERNATIONAL EDITION. Cites a CVE in CISA KEV.
  • Thu 23 Apr, 18:33 UTC. CISA, its first report on the story. CISA Flags Critical Marimo RCE Bug CVE-2026-39987 in KEV. Cites a CVE in CISA KEV.
  • Thu 23 Apr, 19:11 UTC. CISA. CISA Flags Marimo RCE Flaw in KEV, Urges Immediate Patching Action. Cites a CVE in CISA KEV.
  • Fri 29 May, 16:05 UTC. The Hacker News. Attackers Deploy AI LLM Agent After Marimo CVE-2026-39987 Breach. Cites a CVE in CISA KEV.
  • Mon 14 Sep, 14:51 UTC. Infosecurity, its first report on the story. Human Attacker Hits Machine-Speed Exploitation of Marimo RCE. Cites a CVE in CISA KEV. This article, 8th of 8.
  • Known exploited CVE
  • No CVE
  • Larger: an outlet’s first report
  • Square: official source
  • Coverage over time
  • Quiet time, folded
Show all 8 articles as a list
  1. Fri 10 AprDay 02
    1. Attackers exploit Marimo CVE-2026-39987 flaw hours after advisory09:41 · SecurityWeek · First report · Exploited CVE · Known exploited CVE
    2. Marimo flaw lets attackers gain shell within hours of disclosure11:26 · The Hacker News · Known exploited CVE
  2. Sat 11 AprDay 11
    1. CVE-2026-39987: Marimo RCE exploited in hours after disclosure10:21 · Security Affairs · Known exploited CVE
  3. Sun 12 AprDay 21
    1. Security Affairs newsletter Round 572 by Pierluigi Paganini – INTERNATIONAL EDITION09:21 · Security Affairs · Known exploited CVE

  4. Quiet for 11 days

    Thu 23 AprDay 132
    1. CISA Flags Critical Marimo RCE Bug CVE-2026-39987 in KEV18:33 · CISA · official · CISA alert · Picked up again · Known exploited CVE
    2. CISA Flags Marimo RCE Flaw in KEV, Urges Immediate Patching Action19:11 · CISA · official · Known exploited CVE

  5. Quiet for 5 weeks

    Fri 29 MayDay 491
    1. Attackers Deploy AI LLM Agent After Marimo CVE-2026-39987 Breach16:05 · The Hacker News · Picked up again · Known exploited CVE

  6. Quiet for 15 weeks

    Mon 14 SepDay 1571
    1. Human Attacker Hits Machine-Speed Exploitation of Marimo RCE14:51 · Infosecurity · Picked up again · Known exploited CVE · This article, 8th of 8

Sources

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