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Not in CISA KEV
MEDIUM severity

melange has a path traversal in license-path which allows reading files outside workspaceGHSA-2w4f-9fgg-q2v9

MEDIUMFix: chainguard-dev/melange@2f95c9f

GHSA-2w4f-9fgg-q2v9 is a medium-severity (CVSS 5.5) Path Traversal vulnerability in chainguard.dev/melange. A fix is available for chainguard.dev/melange — see the affected versions and patch details below.

Also known asCVE-2026-25145GO-2026-4409
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 1, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-2w4f-9fgg-q2v9.

EPSS Exploitation Probability

via FIRST.org ↗
0.2%probability of exploitation in next 30 days
Lower Risk+0.01%
Lower risk than most CVEs9th percentile — riskier than 9% of all scored CVEsHighest risk
0.00%0.23%0.46%0.69%0.0%0.2%May 26Aug 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
🐹chainguard.dev/melange

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

An attacker who can influence a melange configuration file (e.g., through pull request-driven CI or build-as-a-service scenarios) could read arbitrary files from the host system. The LicensingInfos function in pkg/config/config.go reads license files specified in copyright[].license-path without validating that paths remain within the workspace directory, allowing path traversal via ../ sequences. The contents of the traversed file are embedded into the generated SBOM as license text, enabling exfiltration of sensitive data through build artifacts.

Fix: Merged in commit 2f95c9f4

Acknowledgements

melange thanks Oleh Konko (@1seal) from 1seal for discovering and reporting this issue.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐹Gochainguard.dev/melange≥ 0.14.0&&< 0.40.30.40.3go get chainguard.dev/melange@v0.40.3

Affected Products

1 product · 1 configurations
Application
melangechainguard
≥ 0.14.0 && < 0.40.5
range

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for chainguard.dev/melange, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update chainguard.dev/melange to 0.40.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-2w4f-9fgg-q2v9 is resolved across your whole dependency graph.

  3. Workarounds

    Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

An attacker who can influence a melange configuration file (e.g., through pull request-driven CI or build-as-a-service scenarios) could read arbitrary files from the host system. The `LicensingInfos` function in `pkg/config/config.go` reads license files specified in `copyright[].license-path` without validating that paths remain within the workspace directory, allowing path traversal via `../` sequences. The contents of the traversed file are embedded into the generated SBOM as license text, enabling exfiltration of sensitive data through build artifacts.
O3 Security · Impact-Aware SCA

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GHSA-2w4f-9fgg-q2v9: melange — Fixed in 0.40.3