# CVE-2026-29051

> Vulnerability · severity: **MEDIUM** (CVSS 4.4).

## 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-<pkgname>-<pkgver>-r<epoch>.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.

## Key facts

- **CVE ID:** CVE-2026-29051
- **Published:** 2026-04-24
- **CVSS severity:** MEDIUM
- **CVSS base score:** 4.4
- **CWE codes:** CWE-22

## Affected products

- `chainguard:melange`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-29051

## Citation

> AI Analytics. CVE-2026-29051. Retrieved 2026-08-17 from https://api.ai-analytics.org/cve/CVE-2026-29051. Derived from NIST NVD. Licensed CC0.

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