{"id":"CVE-2026-29050","aliases":["GHSA-98f2-w9h9-7fp9","GO-2026-5279"],"url":"https://o3.security/vulnerability/CVE-2026-29050","summary":"melange has Path Traversal When Resolving External Pipelines via Unvalidated pipeline[].uses","details":"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 `/`.","published":"2026-04-23T23:58:39.668Z","modified":"2026-08-12T03:51:31.427313611Z","cvss":{"score":6.1,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N"},"epss":{"score":0.0014,"percentile":0.03826,"asOf":"2026-08-20"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"chainguard.dev/melange","fixedVersion":"0.43.4"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/29xxx/CVE-2026-29050.json"},{"type":"ADVISORY","url":"https://github.com/chainguard-dev/melange/security/advisories/GHSA-98f2-w9h9-7fp9"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-29050"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:31.427313611Z"}}