CVE-2026-44728 — @babel/plugin-transform-m…
HIGHCVE-2026-44728 is a high-severity (CVSS 8.2) Code Injection vulnerability in @babel/plugin-transform-modules-systemjs. A fix is available for @babel/plugin-transform-modules-systemjs — see the affected versions and patch details below.
Improper Control of Generation of Code when compiling specifically crafted malicious code with @babel/plugin-transform-modules-systemjs
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-44728.
EPSS Exploitation Probability
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
CVE-2026-44728 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 378,156 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
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.
@babel/plugin-transform-modules-systemjsnpmDescription
Impact
Using Babel to compile code that was specifically crafted by an attacker can cause Babel to generate output code that executes arbitrary code.
Known affected plugins are:
@babel/plugin-transform-modules-systemjs@babel/preset-envwhen using themodules: "systemjs"option, as it delegates to@babel/plugin-transform-modules-systemjs
No other plugins under the @babel namespace are impacted.
Users that only compile trusted code are not impacted.
Patches
The vulnerability has been fixed in @babel/[email protected].
Babel also released @babel/[email protected], updating its @babel/plugin-transform-modules-systemjs dependency, to simplify forcing the update if you are using @babel/preset-env directly.
Workarounds
- Pin
@babel/parserto v7.11.5. The downgrade will completely disable string module name parsing, but it would also disable other new language features and the build pipeline may fail as a result. Only do so if you are working on a legacy codebase and can not upgrade@babel/plugin-transform-modules-systemjsto v7.29.4. - Do not use the
modules: "systemjs"option, migrate the codebase to native ES Modules or any other module formats.
Credits
Babel thanks Daniel Cervera for reporting the vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @babel/plugin-transform-modules-systemjs | ≥ 7.12.0&&< 7.29.4 | 7.29.4npm install @babel/plugin-transform-modules-systemjs@7.29.4 |
| 📦npm | @babel/plugin-transform-modules-systemjs | ≥ 8.0.0-alpha.0&&< 8.0.0-alpha.13 | 8.0.0-alpha.13npm install @babel/plugin-transform-modules-systemjs@8.0.0-alpha.13 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @babel/plugin-transform-modules-systemjs, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @babel/plugin-transform-modules-systemjs to 7.29.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-44728 is resolved across your whole dependency graph.
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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-44728 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-44728. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-44728 in your dependencies?
O3 Security finds CVE-2026-44728 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.