Quick answers
- Is CVE-2026-42576 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-42576 being exploited in the wild.
- How severe is CVE-2026-42576?
- Medium severity, with a CVSS score of 6.5, published 9 May 2026.
- Which products and versions are affected?
- Chainguard Apko < 1.2.7; chainguard.dev/apko (Go) < 1.2.7, SEMVER:introduced=0,fixed=1.2.7.
- Is there a fix for CVE-2026-42576?
- Yes. chainguard.dev/apko (Go): upgrade to 1.2.7 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-42576 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-42576?
- Check whether you run Chainguard Apko or chainguard.dev/apko (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- chainguard.dev/apko (Go): upgrade to 1.2.7 or later
go get chainguard.dev/apko@v1.2.7
Technical details
A panic occurs in the `DiscoverKeys` function within `pkg/apk/apk/implementation.go` due to an incorrect type conversion. The code unconditionally type-asserts JWKS keys as `*rsa.PublicKey` without verifying the actual key type. If a remote repository's JWKS endpoint returns a non-RSA key (such as Elliptic Curve/EC), the unchecked assertion triggers a Go panic, crashing the apko process. This affects any workflow involving APK database initialization and key fetching. The issue is fixed in version 1.2.7 by implementing a guarded type assertion.
Affected products
- Chainguard apko < 1.2.7
Identifiers
- CVE-2026-42576
- GHSA-m7hm-vm4x-28jf
- GO-2026-5497
Timeline
- 2026-04-23: patched: Version 1.2.7 released
- 2026-04-23: advisory: GitHub Security Advisory published
- 2026-05-09: disclosed: CVE-2026-42576 published to NVD