CVE-2026-25122 MEDIUM

CVE-2026-25122: apko is vulnerable to unbounded resource consumption in expandapk.Split on attacker-controlled .apk streams

Vendor Chainguard-Dev
Product apko
Weakness CWE-400
Published February 4, 2026
Last update February 4, 2026

CVSS base score

5.5/10
Attack vector Local
Attack complexity Low
Privileges required None
User interaction Required
Confidentiality None
Integrity None

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

What the vulnerability does

01Description

apko allows users to build and publish OCI container images built from apk packages. From version 0.14.8 to before 1.1.0, expandapk.Split drains the first gzip stream of an APK archive via io.Copy(io.Discard, gzi) without explicit bounds. With an attacker-controlled input stream, this can force large gzip inflation work and lead to resource exhaustion (availability impact). The Split function reads the first tar header, then drains the remainder of the gzip stream by reading from the gzip reader directly without any maximum uncompressed byte limit or inflate-ratio cap. A caller that parses attacker-controlled APK streams may be forced to spend excessive CPU time inflating gzip data, leading to timeouts or process slowdown. This issue has been patched in version 1.1.0.

Key dates

02Disclosure timeline

February 4, 2026 CVE published
February 4, 2026 Record updated