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

> Unauthenticated attackers can execute arbitrary Python code via the /api/kernels endpoint in default Mercury deployments.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** GHSA-rv4m-xm3f-3ccq

## What is CVE-2026-111058?

CVE-2026-111058 is a critical code injection vulnerability in mljar mercury, published on 19 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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 execute_request 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.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-111058?

2 open source packages ship an affected version, including mercury.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mercury` | PyPI | All versions | 3.2.6 |
| `mercury` | PyPI | All versions | 3.2.6 |

## How do I fix CVE-2026-111058?

Upgrade mercury to 3.2.6 or later.

## Is CVE-2026-111058 being exploited?

There is no known exploitation of CVE-2026-111058 in the wild and no public exploit code.

Public exploit code:

- Mercury unauth RCE combo: CVE-2026-111058 (kernels) + CVE-2026-111057 (terminals). By 0xNuts (@ExDev994). Authorized testing only. (github_poc): https://github.com/ExDev994/CVE-2026-111058-CVE-2026-111057-mercury-rce

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-111058 and fix it if it is affected.

What it is: CVE-2026-111058 is a critical code injection vulnerability in mljar mercury, published on 19 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-111058 in the wild and no public exploit code.

Affected packages and fixed versions:
- mercury (PyPI): affected all versions; fixed in 3.2.6
- mercury (PyPI): affected all versions; fixed in 3.2.6

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-111058/ (Markdown: https://insights.sbomify.com/CVE-2026-111058/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-111058
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-111058
- OSV: https://osv.dev/vulnerability/CVE-2026-111058

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-111058/
Summaries are generated and may contain mistakes; the official description above is the record.