CVE-2026-29050

Workarounds

Only run melange build against configuration files from trusted sources. In CI systems that build user-supplied melange configs, gate builds behind manual review of pipeline[].uses values and reject any containing .. or leading /.

Credits

melange thanks Oleh Konko (@1seal from 1seal.org) for discovering and reporting this issue.

An attacker who can influence a melange configuration file, for example through pull-request-driven CI or build-as-a-service scenarios, could set pipeline[].uses to a value containing ../ sequences or an absolute path. The (*Compiled).compilePipeline function in pkg/build/compile.go passed uses directly to filepath.Join(pipelineDir, uses + ".yaml") without validating the value, so the resolved path could escape each --pipeline-dir and read an arbitrary YAML-parseable file visible to the melange process. Because the loaded file is subsequently interpreted as a melange pipeline and its runs: block is executed via /bin/sh -c in the build sandbox, this additionally allowed shell commands sourced from an out-of-tree file to run during the build, bypassing the review boundary that normally covers the in-tree pipeline definition.

Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.

CVE-2026-29050 has a CVSS score of 6.1 (Medium). The vector is requires local access, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.43.4); upgrading removes the vulnerable code path.

Kodem intelligence

Fixed in melange v0.43.4 via commit 5829ca4. The fix rejects uses values that are absolute paths or contain .., and verifies (via filepath.Rel after filepath.Clean) that the resolved target remains within the pipeline directory.

1. What is CVE-2026-29050? CVE-2026-29050 is a medium-severity path traversal vulnerability in chainguard.dev/melange (go), affecting versions >= 0.32.0, < 0.43.4. It is fixed in 0.43.4. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
2. How severe is CVE-2026-29050? CVE-2026-29050 has a CVSS score of 6.1 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of chainguard.dev/melange are affected by CVE-2026-29050? chainguard.dev/melange (go) versions >= 0.32.0, < 0.43.4 is affected.
4. Is there a fix for CVE-2026-29050? Yes. CVE-2026-29050 is fixed in 0.43.4. Upgrade to this version or later.
5. Is CVE-2026-29050 exploitable, and should I be worried? Whether CVE-2026-29050 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-29050 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-29050? Upgrade chainguard.dev/melange to 0.43.4 or later.