What is CVE-2026-15895?

CVE-2026-15895 is a high-severity OS command injection vulnerability in jsii-diff (npm), affecting versions < 1.131.0. It is fixed in 1.131.0. Untrusted input reaches a shell command, allowing arbitrary commands to run on the host.

How severe is CVE-2026-15895?

CVE-2026-15895 has a CVSS score of 7.8 (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 jsii-diff are affected by CVE-2026-15895?

jsii-diff (npm) versions < 1.131.0 is affected.

Is there a fix for CVE-2026-15895?

Yes. CVE-2026-15895 is fixed in 1.131.0. Upgrade to this version or later.

Is CVE-2026-15895 exploitable, and should I be worried?

Whether CVE-2026-15895 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.

What actually determines whether CVE-2026-15895 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-2026-15895?

Upgrade jsii-diff to 1.131.0 or later.

CVE-2026-15895 in jsii-diff

Q: How severe is CVE-2026-15895?

CVE-2026-15895 has a CVSS score of 7.8 (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.

Q: Which versions of jsii-diff are affected by CVE-2026-15895?

jsii-diff (npm) versions < 1.131.0 is affected.

Q: Is there a fix for CVE-2026-15895?

Yes. CVE-2026-15895 is fixed in 1.131.0. Upgrade to this version or later.

Q: Is CVE-2026-15895 exploitable, and should I be worried?

Whether CVE-2026-15895 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.

Q: What actually determines whether CVE-2026-15895 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.

Q: How do I fix CVE-2026-15895?

Upgrade jsii-diff to 1.131.0 or later.

Summary

jsii-diff: Command Injection via npm: package argument

jsii-diff is a command line tool to compare the API differences between two jsii assemblies, and report errors if there are backwards-incompatible changes to the API. An issue exists where specially formatted command line arguments can be used to execute shell commands via this tool.

Workarounds

If you are unable to update, make sure only trusted actors can control the arguments passed to jsii-diff.

References

If you have any questions or comments about this advisory, AWS asks that you contact AWS Security via the vulnerability reporting page or directly via email to [email protected]. Please do not create a public GitHub issue.

Impact

jsii-diff supports downloading packages to compare directly from NPM, so that you can compare a proposed candidate version of your jsii package with an already-published version, by passing an argument that looks like npm:<package-specifier>. For example:

jsii-diff npm:my-package@latest .

By injecting a ; into the package-specifier part of that command, jsii-diff can be tricked into running shell commands. For example:

jsii-diff "npm:lodash; touch /tmp/123" .

This allows anyone that can control the command-line arguments to jsii-diff to run arbitrary commands with the same permissions as the jsii-diff command itself.

Untrusted input reaches a shell command, allowing arbitrary commands to run on the host. Typical impact: code execution in the application's environment.

CVE-2026-15895 has a CVSS score of 7.8 (High). The vector is requires local access, no privileges required, and user interaction required. 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 (1.131.0); upgrading removes the vulnerable code path.

Affected versions

jsii-diff (< 1.131.0)

Security releases

jsii-diff → 1.131.0 (npm)

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.

Already deployed Kodem?

See it in your environment New to Kodem? Get a demo →

Remediation advice

This issue has been addressed in jsii-diff version 1.131.0. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.

Frequently Asked Questions

What is CVE-2026-15895? CVE-2026-15895 is a high-severity OS command injection vulnerability in jsii-diff (npm), affecting versions < 1.131.0. It is fixed in 1.131.0. Untrusted input reaches a shell command, allowing arbitrary commands to run on the host.
How severe is CVE-2026-15895? CVE-2026-15895 has a CVSS score of 7.8 (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 jsii-diff are affected by CVE-2026-15895? jsii-diff (npm) versions < 1.131.0 is affected.
Is there a fix for CVE-2026-15895? Yes. CVE-2026-15895 is fixed in 1.131.0. Upgrade to this version or later.
Is CVE-2026-15895 exploitable, and should I be worried? Whether CVE-2026-15895 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-2026-15895 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-2026-15895? Upgrade jsii-diff to 1.131.0 or later.