Summary
kaniko unpacks build context archives using filepath.Join(dest, cleanedName) without enforcing that the final path stays within dest. A tar entry like ../outside.txt escapes the extraction root and writes files outside the destination directory. In environments with registry authentication, this can be chained with docker credential helpers to achieve code execution within the executor process. Affected versions >= 1.25.4, <= 1.25.9.
Fix: Merged with PR #326, uses securejoin for path resolution in tar extraction.
Acknowledgements
kaniko thanks Oleh Konko from 1seal for discovering and reporting this issue.
Impact
Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.
CVE-2026-28406 has a CVSS score of 8.2 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.25.10); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-28406? CVE-2026-28406 is a high-severity path traversal vulnerability in github.com/chainguard-dev/kaniko (go), affecting versions >= 1.25.4, < 1.25.10. It is fixed in 1.25.10. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
- How severe is CVE-2026-28406? CVE-2026-28406 has a CVSS score of 8.2 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/chainguard-dev/kaniko are affected by CVE-2026-28406? github.com/chainguard-dev/kaniko (go) versions >= 1.25.4, < 1.25.10 is affected.
- Is there a fix for CVE-2026-28406? Yes. CVE-2026-28406 is fixed in 1.25.10. Upgrade to this version or later.
- Is CVE-2026-28406 exploitable, and should I be worried? Whether CVE-2026-28406 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-28406 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-28406? Upgrade
github.com/chainguard-dev/kanikoto 1.25.10 or later.