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MEDIUM severity

GHSA-2w4f-9fgg-q2v9 melange

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.

melange has a path traversal in license-path which allows reading files outside workspace

Also known asCVE-2026-25145GO-2026-4409
Published
Feb 4, 2026
Updated
Sep 10, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 18, 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 Risk0.00%
Lower risk than most CVEs7th percentile — riskier than 7% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

GHSA-2w4f-9fgg-q2v9 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

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/melange0.14.0&&< 0.40.30.40.3go get chainguard.dev/melange@v0.40.3

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

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-2w4f-9fgg-q2v9 can be triaged on real exposure rather than presence alone.

Tailored to GHSA-2w4f-9fgg-q2v9. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

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

Is GHSA-2w4f-9fgg-q2v9 in your dependencies?

O3 Security finds GHSA-2w4f-9fgg-q2v9 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-2w4f-9fgg-q2v9: melange (Medium 5.5) | O3 Security