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HIGH severity

GHSA-wcx4-wpfv-mc5c jsii-diff

HIGH

GHSA-wcx4-wpfv-mc5c is a high-severity (CVSS 7.8) OS Command Injection vulnerability in jsii-diff. A fix is available for jsii-diff — see the affected versions and patch details below.

jsii-diff: Command Injection via npm: package argument

Also known asCVE-2026-15895
Published
Aug 7, 2026
Updated
Aug 7, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 19, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.1%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs64th percentile — riskier than 64% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

GHSA-wcx4-wpfv-mc5c plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

0other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
jsii-diffnpm
29Kdownloads / week

Description

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:

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.

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 derivative code is patched to incorporate the new fixes.

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.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmjsii-diffall versions1.131.0npm install jsii-diff@1.131.0

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for jsii-diff, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update jsii-diff to 1.131.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wcx4-wpfv-mc5c is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-wcx4-wpfv-mc5c can be triaged on real exposure rather than presence alone.

Tailored to GHSA-wcx4-wpfv-mc5c. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## 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: ``` jsii-diff npm:my-package@late
O3 Security · Impact-Aware SCA

Is GHSA-wcx4-wpfv-mc5c in your dependencies?

O3 Security finds GHSA-wcx4-wpfv-mc5c across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-wcx4-wpfv-mc5c: jsii-diff (High 7.8) | O3 Security