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HIGH severity

melange: Incomplete package integrity verification allows data section substitutionGHSA-fpg8-7664-jc5q

HIGH

GHSA-fpg8-7664-jc5q is a high-severity (CVSS 8.3) CWE-345 vulnerability in chainguard.dev/apko. A fix is available for chainguard.dev/apko — see the affected versions and patch details below.

Also known asCVE-2026-54174GO-2026-5968
Published
Updated
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed
Exploitation data as of Oct 24, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • A successful exploit gives an attacker total control of the affected component, not partial access.
  • 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-fpg8-7664-jc5q.

EPSS Exploitation Probability

via FIRST.org ↗
0.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs4th percentile — riskier than 4% of all scored CVEsHighest risk
0.00%0.22%0.44%0.66%0.2%0.2%Oct 26Oct 26

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

How urgent is this, really

GHSA-fpg8-7664-jc5q by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 395,249 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

2 pkgs affected
🐹chainguard.dev/apko🐹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

melange allows users to build apk packages using declarative pipelines. Apko prior to version 1.2.9, corresponding to melange prior to version 0.50.4, verified the control section hash (.PKGINFO etc.) against the signed APKINDEX, but never verified the data section hash (the actual package files that get installed). An attacker who could compromise a mirror, poison a cache, or MITM a package fetch could substitute arbitrary file contents while the control hash check still passed. Apko version 1.2.9 and melange version 0.50.4 contain a fix.

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
🐹Gochainguard.dev/apkoall versions1.2.9go get chainguard.dev/apko@v1.2.9
🐹Gochainguard.dev/melangeall versions0.50.4go get chainguard.dev/melange@v0.50.4

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/apko, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update chainguard.dev/apko to 1.2.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fpg8-7664-jc5q 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.

Frequently Asked Questions

Previously, Apko verified the control section hash (`.PKGINFO` etc.) against the signed `APKINDEX`, but never verified the data section hash (the actual package files that get installed). An attacker who could compromise a mirror, poison a cache, or MITM a package fetch could substitute arbitrary file contents while the control hash check still passed.
O3 Security · Impact-Aware SCA

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melange: Incomplete package integrity verification allows…