CVE-2026-42575 apko doesn't verify downloaded apk packages against APKINDEX checksum (package substitution possible)
Attackers can substitute malicious APK packages during image builds because apko fails to verify downloaded package checksums against the signed index.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-42575?
CVE-2026-42575 is a high-severity vulnerability in chainguard-dev apko, published on 9 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Which versions are affected by CVE-2026-42575?
3 open source packages ship an affected version, including chainguard.dev/apko.
| Package | Affected | Fixed in |
|---|---|---|
chainguard.dev/apko Go | All versions | 1.2.7 |
chainguard.dev/apko Go | All versions | 1.2.7 |
chainguard.dev/apko Go | All versions | 1.2.7 |
How do I fix CVE-2026-42575?
Upgrade chainguard.dev/apko to 1.2.7 or later.
Is CVE-2026-42575 being exploited?
There is no known exploitation of CVE-2026-42575 in the wild and no public exploit code.
Sources
Also known as CLEANSTART-2026-SY69656, GHSA-hcwr-pq9g-rq3m, GO-2026-5422, MINI-4rx3-rv43-cww4, MINI-7vj8-gqqv-55rj, MINI-8m8f-gpvp-f7x4.