# CVE-2026-43991: JunoClaw: plugin-shell shell-injection bypass via substring blocklist

> Attackers can bypass command safety checks in JunoClaw to execute arbitrary commands on the host system.

- **Severity:** High 8.4 (`CVSS:3.1/AV:L/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:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 May 2026
- **Updated:** 13 May 2026
- **Also known as:** GHSA-fvq5-79h6-952c

## What is CVE-2026-43991?

CVE-2026-43991 is a high-severity command injection vulnerability in Dragonmonk111 junoclaw, published on 12 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

JunoClaw is an agentic AI platform built on Juno Network. Prior to 0.x.y-security-1, substring-based blocklist in plugin-shell's command-safety check could be bypassed by adversarial argument constructions, allowing unauthorized command execution on the host when combined with the companion advisory. Pre-patch, the check was applied to the raw command string rather than the parsed first token. This vulnerability is fixed in 0.x.y-security-1.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command), CWE-184 (Incomplete List of Disallowed Inputs)

## Which versions are affected by CVE-2026-43991?


## How do I fix CVE-2026-43991?

No fix has been published for CVE-2026-43991 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-43991 being exploited?

There is no known exploitation of CVE-2026-43991 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-43991 and fix it if it is affected.

What it is: CVE-2026-43991 is a high-severity command injection vulnerability in Dragonmonk111 junoclaw, published on 12 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-43991 in the wild and no public exploit code.

Affected product: Dragonmonk111 junoclaw. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-43991/ (Markdown: https://insights.sbomify.com/CVE-2026-43991/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43991
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43991
- OSV: https://osv.dev/vulnerability/CVE-2026-43991

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43991/
Summaries are generated and may contain mistakes; the official description above is the record.