CVE-2026-44290 — protobufjs
HIGHCVE-2026-44290 is a high-severity (CVSS 7.5) CWE-1321 vulnerability in protobufjs. A fix is available for protobufjs — see the affected versions and patch details below.
protobufjs: Process-wide denial of service through unsafe option paths
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- 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-2026-44290.
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-2026-44290 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.
protobufjsnpmDescription
Summary
protobufjs allowed certain schema option paths to traverse through inherited object properties while applying options. A crafted protobuf schema or JSON descriptor could cause option handling to write to properties on global JavaScript constructors, corrupting process-wide built-in functionality.
Impact
An attacker who can provide or influence protobuf schemas or JSON descriptors may be able to corrupt built-in process state in a way that causes subsequent application code or protobufjs code to fail. This can result in a persistent denial of service for the lifetime of the affected process.
This issue affects applications that parse or load protobuf schemas or descriptors from untrusted sources. Applications that use bundled, generated, or otherwise trusted schemas to decode untrusted protobuf message payloads are not directly affected.
The issue is not known to allow code execution by itself.
Preconditions
- The application must allow an attacker to control or influence a protobuf schema or JSON descriptor.
- The application must parse or load that schema through protobufjs reflection APIs such as
parse,Root.load,Root.loadSync, orRoot.fromJSON. - The crafted input must contain option paths that reach unsafe inherited properties during option processing.
Workarounds
Do not parse or load protobuf schemas or JSON descriptors from untrusted sources with affected versions. If untrusted schemas must be accepted, validate or reject option names containing unsafe property path components before loading them, and run schema processing in an isolated process.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | protobufjs | all versions | 7.5.6npm install protobufjs@7.5.6 |
| 📦npm | protobufjs | ≥ 8.0.0&&< 8.0.2 | 8.0.2npm install protobufjs@8.0.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for protobufjs, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update protobufjs to 7.5.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-44290 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-2026-44290 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-44290. 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-2026-44290 in your dependencies?
O3 Security finds CVE-2026-44290 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.