CVE-2026-44295 — protobufjs-cli
HIGHCVE-2026-44295 is a high-severity (CVSS 8.7) Code Injection vulnerability in protobufjs-cli. A fix is available for protobufjs-cli — see the affected versions and patch details below.
protobufjs-cli: Code injection in pbjs static output from crafted schema names
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-2026-44295.
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-2026-44295 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 378,567 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.
protobufjs-clinpmDescription
Summary
pbjs static code generation could emit unsafe JavaScript identifiers derived from schema-controlled names. When generating static JavaScript from a crafted schema or JSON descriptor, certain namespace, enum, service, or derived full names could be written into the generated output without sufficient sanitization.
Impact
An attacker who can provide or influence schemas passed to pbjs may be able to cause generated JavaScript output to contain attacker-controlled code. The injected code would run if the generated file is later executed or imported by the application or build process.
This affects the protobufjs CLI static code generation path. Applications that only use trusted schemas, or that do not execute generated output from untrusted schemas, are not directly affected.
Preconditions
- The application or build process must run
pbjsstatic code generation on a schema or JSON descriptor influenced by an attacker. - The attacker-controlled input must contain crafted schema names that reach generated JavaScript output.
- The generated JavaScript file must subsequently be executed, imported, or otherwise evaluated.
Workarounds
Do not run affected versions of pbjs static code generation on untrusted schemas or descriptors. If untrusted schemas must be accepted, validate schema names before code generation and run generation in an isolated environment.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | protobufjs-cli | all versions | 1.2.1npm install protobufjs-cli@1.2.1 |
| 📦npm | protobufjs-cli | ≥ 2.0.0&&< 2.0.2 | 2.0.2npm install protobufjs-cli@2.0.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for protobufjs-cli, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update protobufjs-cli to 1.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-44295 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-2026-44295 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-44295. 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-2026-44295 in your dependencies?
O3 Security finds CVE-2026-44295 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.