CVE intelligence and bounded remediation

CVE-2026-29051 — melange allows users to build apk packages using declarative pipelines

Medium CVSS 4.4

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/l…

Severity
Medium
CVSS
4.4 (3.1)
Published
2026-04-24
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-22

Affected products

  • chainguard / melange

Matched remediation archetype

Path traversal, unsafe upload, and file handling

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Check exposure

  • Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
  • Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
  • Review canonicalization and containment checks across supported operating systems and storage backends.

Remediate safely

  • Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
  • Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
  • Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.

Authoritative sources

Complete CVE record and remediation plan

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