# CVE-2026-90813: cosmicstack-labs mercury-agent Shell Command Execution permissions.ts checkShellCommand validate before canonicalize

> Remote attackers can execute arbitrary shell commands in cosmicstack-labs mercury-agent due to improper validation order in permission checks.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Sep 2026
- **Updated:** 14 Sep 2026
- **Also known as:** GHSA-9hv7-6jr2-3g59

## What is CVE-2026-90813?

CVE-2026-90813 is a medium-severity command injection vulnerability in cosmicstack-labs mercury-agent, published on 14 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability was detected in cosmicstack-labs mercury-agent up to 1.1.13. Affected is the function checkShellCommand of the file src/capabilities/permissions.ts of the component Shell Command Execution. The manipulation results in incorrect behavior order: validate before canonicalize. The attack may be launched remotely. The exploit is now public and may be used. The project was informed of the problem early through an issue report but has not responded yet.

Weakness: CWE-180 (Incorrect Behavior Order: Validate Before Canonicalize), CWE-179 (Incorrect Behavior Order: Early Validation)

## Which versions are affected by CVE-2026-90813?


## How do I fix CVE-2026-90813?

No fix has been published for CVE-2026-90813 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-90813 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-90813 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90813 and fix it if it is affected.

What it is: CVE-2026-90813 is a medium-severity command injection vulnerability in cosmicstack-labs mercury-agent, published on 14 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-90813 exists.

Affected product: cosmicstack-labs mercury-agent. 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-2026-90813/ (Markdown: https://insights.sbomify.com/CVE-2026-90813/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90813
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90813
- OSV: https://osv.dev/vulnerability/CVE-2026-90813

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90813/
Summaries are generated and may contain mistakes; the official description above is the record.