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

> An attacker can exhaust disk space on CI build runners by providing a malicious URI in melange build configs, causing unbounded downloads.

- **Severity:** Medium 4.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 6 Mar 2026
- **Updated:** 7 Jul 2026
- **Also known as:** GHSA-7rp8-r62p-q6wc, GO-2026-4588

## What is CVE-2026-29049?

CVE-2026-29049 is a medium-severity denial of service vulnerability in chainguard-dev melange, published on 6 Mar 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-918 (Server-Side Request Forgery), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-29049?

3 open source packages ship an affected version, including chainguard.dev/melange. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `chainguard.dev/melange` | Go | All versions | None |
| `chainguard.dev/melange` | Go | All versions | 0.43.4 |
| `chainguard.dev/melange` | Go | All versions | 0.43.4 |

Products: Chainguard Melange.

## How do I fix CVE-2026-29049?

Upgrade chainguard.dev/melange to 0.43.4 or later.

## Is CVE-2026-29049 being exploited?

There is no known exploitation of CVE-2026-29049 in the wild and no public exploit code.

## Other vulnerabilities in chainguard-dev melange

- [CVE-2026-24843](https://insights.sbomify.com/CVE-2026-24843/): melange QEMU runner could write files outside workspace directory (high 8.2)
- [CVE-2026-24844](https://insights.sbomify.com/CVE-2026-24844/): melange pipeline working-directory could allow command injection (high 7.8)
- [CVE-2026-25143](https://insights.sbomify.com/CVE-2026-25143/): melange affected by potential host command execution via license-check YAML mode patch pipeline (high 7.8)
- [CVE-2026-29050](https://insights.sbomify.com/CVE-2026-29050/): melange has Path Traversal When Resolving External Pipelines via Unvalidated pipeline[].uses (medium 6.1)
- [CVE-2026-25145](https://insights.sbomify.com/CVE-2026-25145/): melange has a path traversal in license-path which allows reading files outside workspace (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-29049 and fix it if it is affected.

What it is: CVE-2026-29049 is a medium-severity denial of service vulnerability in chainguard-dev melange, published on 6 Mar 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-29049 in the wild and no public exploit code.

Affected packages and fixed versions:
- chainguard.dev/melange (Go): affected all versions; no fix listed
- chainguard.dev/melange (Go): affected all versions; fixed in 0.43.4
- chainguard.dev/melange (Go): affected all versions; fixed in 0.43.4

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-29049/ (Markdown: https://insights.sbomify.com/CVE-2026-29049/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-29049
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-29049
- OSV: https://osv.dev/vulnerability/CVE-2026-29049

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-29049/
Summaries are generated and may contain mistakes; the official description above is the record.