# CVE-2026-29051: melange has Path Traversal via .PKGINFO in --persist-lint-results > Attackers can write arbitrary JSON files via path traversal in melange when using the opt-in persist-lint-results flag, potentially clobbering other artifacts. - **Severity:** Medium 4.4 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Local or same network only - **Victim action needed:** A user has to click or open something - **Fix available:** Yes - **Published:** 24 Apr 2026 - **Updated:** 24 Apr 2026 - **Also known as:** GHSA-q2pw-xx38-p64j, GO-2026-5562 ## What is CVE-2026-29051? CVE-2026-29051 is a medium-severity path traversal vulnerability in chainguard-dev melange, published on 24 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link. ### Official description melange allows users to build apk packages using declarative pipelines. Starting in version 0.32.0 and prior to version 0.43.4, `melange lint --persist-lint-results` (opt-in flag, also usable via `melange build --persist-lint-results`) constructs output file paths by joining `--out-dir` with the `arch` and `pkgname` values read from the `.PKGINFO` control file of the APK being linted. In affected versions these values were not validated for path separators or `..` sequences, so an attacker who can supply an APK to a melange-based lint/build pipeline (e.g. CI that lints third-party APKs, or build-as-a-service) could cause melange to write `lint---r.json` to an arbitrary `.json` path reachable by the melange process. The written file is a JSON lint report whose content is partially attacker-influenced. There is no direct code-execution path, but the write can clobber other JSON artifacts on the filesystem. The issue only affects deployments that explicitly pass `--persist-lint-results`; the flag is off by default. The issue is fixed in melange v0.43.4 by validating `arch` and `pkgname` for `..`, `/`, and `filepath.Separator` before path construction in `pkg/linter/results.go` (commit 84f3b45). As a workaround, do not pass `--persist-lint-results` when linting or building APKs whose `.PKGINFO` contents are not fully trusted. Running melange as a low-privileged user and confining writes to an isolated directory also limits impact. Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) ## Which versions are affected by CVE-2026-29051? 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 | From 0.32.0 | 0.43.4 | | `chainguard.dev/melange` | Go | From 0.32.0 | 0.43.4 | | `chainguard.dev/melange` | Go | From 0.32.0 | 0.43.4 | Products: Chainguard Melange. ## How do I fix CVE-2026-29051? Upgrade chainguard.dev/melange to 0.43.4 or later. ## Is CVE-2026-29051 being exploited? There is no known exploitation of CVE-2026-29051 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-2026-29051 and fix it if it is affected. What it is: CVE-2026-29051 is a medium-severity path traversal vulnerability in chainguard-dev melange, published on 24 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link. Exploitation: There is no known exploitation of CVE-2026-29051 in the wild and no public exploit code. Affected packages and fixed versions: - chainguard.dev/melange (Go): affected from 0.32.0; fixed in 0.43.4 - chainguard.dev/melange (Go): affected from 0.32.0; fixed in 0.43.4 - chainguard.dev/melange (Go): affected from 0.32.0; 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-2026-29051/ (Markdown: https://insights.sbomify.com/CVE-2026-29051/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-29051 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-29051 - OSV: https://osv.dev/vulnerability/CVE-2026-29051 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-29051/ Summaries are generated and may contain mistakes; the official description above is the record.