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apko affected by potential unbounded resource consumption in expandapk.ExpandApk on attacker-controlled .apk streams

High severity GitHub Reviewed Published Feb 3, 2026 in chainguard-dev/apko • Updated Feb 4, 2026

Package

gomod chainguard-dev/apko (Go)

Affected versions

> 0.14.8, < 1.1.0

Patched versions

1.1.0

Description

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.

Fix: Fixed in 2be3903. Released in 1.1.0.

Acknowledgements

apko thanks Oleh Konko (@1seal) from 1seal for discovering and reporting this issue.

References

@antitree antitree published to chainguard-dev/apko Feb 3, 2026
Published to the GitHub Advisory Database Feb 4, 2026
Reviewed Feb 4, 2026
Published by the National Vulnerability Database Feb 4, 2026
Last updated Feb 4, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(16th percentile)

Weaknesses

Uncontrolled Resource Consumption

The product does not properly control the allocation and maintenance of a limited resource. Learn more on MITRE.

CVE ID

CVE-2026-25140

GHSA ID

GHSA-f4w5-5xv9-85f6

Source code

Credits

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