Vulnerability · Published May 9, 2026 · Assigned by GitHub_M
CVE-2026-42575apko doesn't verify downloaded apk packages against APKINDEX checksum (package substitution possible)
High 7.5
In plain English
A high-severity insufficient verification of data authenticity in apko from chainguard-dev. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
apko allows users to build and publish OCI container images built from apk packages. Prior to version 1.2.7, apko verifies the signature on APKINDEX.tar.gz but never compares individually downloaded .apk packages against the checksum recorded in the signed index. The checksum is parsed and available via ChecksumString(), and the downloaded package control hash is computed, but the two values are never compared in getPackageImpl(). Mismatched packages are silently accepted. An attacker who can substitute download responses (compromised mirror, HTTP repository, poisoned CDN cache) can install arbitrary packages into built images. This issue has been patched in version 1.2.7.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | chainguard.dev/apko | 1.2.7 | GHSA-hcwr-pq9g-rq3m |
| Go | chainguard.dev/apko | 1.2.7 | GO-2026-5422 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| chainguard-dev | apko | < 1.2.7 |
Weakness: CWE-345, CWE-494 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N