CVE-2026-44289 — protobufjs
HIGHCVE-2026-44289 is a high-severity (CVSS 7.5) CWE-674 vulnerability in protobufjs. A fix is available for protobufjs — see the affected versions and patch details below.
protobufjs: Denial of service through unbounded protobuf recursion
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-2026-44289.
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-2026-44289 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.
protobufjsnpmDescription
Summary
protobufjs could recurse without a depth limit while decoding nested protobuf data. This affected both skipping unknown group fields and generated decoding of nested message fields.
A crafted protobuf binary payload could cause the JavaScript call stack to be exhausted during decoding.
Impact
An attacker who can provide protobuf binary data decoded by an application may be able to crash the process or otherwise cause decoding to fail with a stack overflow.
This affects applications that decode untrusted protobuf binary input with affected versions.
Preconditions
- The application must decode protobuf binary data influenced by an attacker.
- The crafted input must contain deeply nested protobuf structures, such as nested group tags or nested message fields.
- The affected decoder path must process the crafted input.
Workarounds
Avoid decoding untrusted protobuf binary data with affected versions. If immediate upgrade is not possible, reject excessively nested messages at an outer protocol boundary where feasible, or isolate protobuf decoding in a process that can be safely restarted.
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-2026-44289 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-2026-44289 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-44289. 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-2026-44289 in your dependencies?
O3 Security finds CVE-2026-44289 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.