# CVE-2026-18997: cosmicstack-labs mercury-agent bg agent.ts Agent.handleBgCommand authorization

> Remote attackers can bypass authorization in the background command handler to execute unauthorized actions, requiring immediate attention from users of the library.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/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:** 6 Aug 2026
- **Updated:** 6 Aug 2026
- **Also known as:** GHSA-9hrj-55h5-5mr2

## What is CVE-2026-18997?

CVE-2026-18997 is a medium-severity missing authorization vulnerability in cosmicstack-labs mercury-agent, published on 6 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability was found in cosmicstack-labs mercury-agent up to 1.1.12. This issue affects the function Agent.handleBgCommand of the file src/core/agent.ts of the component bg Command Handler. Performing a manipulation results in incorrect authorization. It is possible to initiate the attack remotely. The exploit has been made public and could be used. The project was informed of the problem early through an issue report but has not responded yet.

Weakness: CWE-863 (Incorrect Authorization), CWE-285 (Improper Authorization)

## Which versions are affected by CVE-2026-18997?


## How do I fix CVE-2026-18997?

No fix has been published for CVE-2026-18997 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-18997 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-18997 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-18997 and fix it if it is affected.

What it is: CVE-2026-18997 is a medium-severity missing authorization vulnerability in cosmicstack-labs mercury-agent, published on 6 Aug 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-2026-18997 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-2026-18997/ (Markdown: https://insights.sbomify.com/CVE-2026-18997/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18997
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18997
- OSV: https://osv.dev/vulnerability/CVE-2026-18997

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-18997/
Summaries are generated and may contain mistakes; the official description above is the record.