---
title: "CVE-2026-111058: Mercury: Unauthenticated Remote Code Execution via /api/kernels"
url: https://erroneo.us/security/cve/CVE-2026-111058/
description: "CVE-2026-111058 (mercury (PyPI)): Mercury is a Python framework for sharing Jupyter notebooks as web applications and dashboards. Prior to 3.2.6, default…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-10-19
date_modified: 2026-10-19
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-111058"
kev: false
cvss: 9.8
epss: 0.00437
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-111058: Mercury: Unauthenticated Remote Code Execution via /api/kernels

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.4% , percentile 37: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 37% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes mercury (PyPI) <= 3.2.5, fixed in 3.2.6 . Check your lockfile, including transitive dependencies.

## What it is

Mercury is a Python framework for sharing Jupyter notebooks as web applications and dashboards. Prior to 3.2.6, default tokenless deployments allow anonymous clients to create Jupyter kernels and send executerequest messages containing arbitrary Python. The endpoint blocklist does not cover /api/kernels, and the websocket wrapper previously tracked idle activity without authorizing executable messages. This issue is fixed in version 3.2.6.

## Affected packages

- PyPI `mercury` <= 3.2.5 → fixed: 3.2.6

## Affected products (CVE record)

- mljar mercury: < 3.2.6

## Severity

- GitHub_M CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.44% probability of exploitation activity in the next 30 days; percentile 37.

## Sources

- [GitHub Advisory GHSA-rv4m-xm3f-3ccq](https://github.com/advisories/GHSA-rv4m-xm3f-3ccq)
- [CVE.org record CVE-2026-111058](https://www.cve.org/CVERecord?id=CVE-2026-111058)
- [NVD entry CVE-2026-111058](https://nvd.nist.gov/vuln/detail/CVE-2026-111058)
- [github.com](https://github.com/mljar/mercury/security/advisories/GHSA-rv4m-xm3f-3ccq)
- [github.com](https://github.com/mljar/mercury/commit/73a40ceb0becf057f495a5738ad7f5a5222a53e1)
- [github.com](https://github.com/mljar/mercury/releases/tag/3.2.6)

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Source page: https://erroneo.us/security/cve/CVE-2026-111058/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt