jsii-diff: Command Injection via npm: package argument

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.4 · CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-15895: 1.08% estimated exploitation activity in the next 30 days; percentile 65.16 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary 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. 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: By injecting a ; into the package-specifier part of that command, jsii-diff can be tricked into running shell commands. For example: 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. Patches This issue has been addressed in jsii-diff version 1.131.0. We recommend upgrading to the latest version and ensuring any forked or…

Published by the source

7 Aug 2026, 18:15 UTC

Last modified by the source

7 Aug 2026, 18:15 UTC

Source last checked

26 Oct 2026, 13:01 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-wcx4-wpfv-mc5c

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# Patch Next advisory brief: CVE-2026-15895

Advisory: jsii-diff: Command Injection via npm: package argument
IDs: CVE-2026-15895, GHSA-wcx4-wpfv-mc5c
Record: https://patchnext.com/advisories/cve-2026-15895 (revision 1, source checked 26 Oct 2026, 13:01 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: jsii-diff 1.131.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm jsii-diff: affected < 1.131.0; fixed in 1.131.0

## Suggested inspection (read-only)
- `npm ls jsii-diff --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on jsii-diff.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-wcx4-wpfv-mc5c (GitHub-reviewed advisory GHSA-wcx4-wpfv-mc5c lists affected ranges: npm jsii-diff >=0 <1.131.0)

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