CVE-2026-29050
MediumCVSS 6.1Exploitation Probability (EPSS)
Low risk3th percentile - higher than 3% of all known CVEs
Summary
melange (a tool for building apk packages using declarative pipelines) from version 0.32.0 to before 0.43.4 allows an attacker who can influence a melange configuration file to 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 validation, so the resolved path could escape --pipeline-dir and read any YAML-parseable file visible to the melange process. Because the loaded file is interpreted as a melange pipeline and its runs: block is executed via /bin/sh -c in the build sandbox, this allowed shell commands from an out-of-tree file to run during the build, bypassing review. Fixed in melange v0.43.4 (commit 5829ca4).
Risk Assessment
An attacker able to influence melange configuration (e.g., via pull-request-driven CI) can execute arbitrary shell commands in the build sandbox and read arbitrary YAML files, bypassing code review.
Recommendation
Upgrade melange to version 0.43.4 or later; until then, only run melange build against trusted configurations and manually review pipeline[].uses values.
Other vulnerabilities in melange
See all- CVE-2026-29051Medium
melange versions 0.32.0 through before 0.43.4 construct output file paths in --persist-lint-results by joining --out-dir with arch and pkgname from the APK's .PKGINFO without validating path separators or '..' sequences. An attacker supplying an APK to a melange lint/build pipeline could cause a JSON lint report to be written to an arbitrary reachable path. There is no direct code execution, but other JSON artifacts can be clobbered. The issue is fixed in 0.43.4.
- CVE-2026-29049Medium
Melange version 0.40.5 and earlier downloads URIs from build configs using io.Copy without any size limit or HTTP client timeout. An attacker-controlled URI in a melange config can cause unbounded disk writes, exhausting disk space on the build runner.
Original NVD description (English source)
melange allows users to build apk packages using declarative pipelines. Starting in version 0.32.0 and prior to version 0.43.4, 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. The issue is 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. As a workaround, 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 `/`.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS