Mercury: Unauthenticated Remote Code Execution in /api/terminals - access control bypass

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Mercury is a Python framework for sharing Jupyter notebooks as web applications and dashboards. From 3.0.0 until 3.2.4, a missing comma in BLOCKED_PATTERNS concatenates the /lab and /api/terminals regular-expression literals. Requests to /api/terminals therefore bypass the anonymous endpoint blocklist and reach Jupyter Server's terminal API. An unauthenticated attacker can use the resulting interactive operating-system shell to execute commands and access data available to the Mercury process. This issue is fixed in version 3.2.4.

Source published

19 Oct 2026 16:04:07 UTC

Source modified

28 Oct 2026 15:31:24 UTC

Observed here

28 Oct 2026 16:46:48 UTC

Source terms

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CVSS 3.1 · 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H