CVE-2023-36665
CRITICALCVE-2023-36665 is a critical-severity (CVSS 9.8) CWE-1321 vulnerability in protobufjs. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether CVE-2023-36665 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
protobufjs Prototype Pollution vulnerability
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
protobufjsnpmDescription
"protobuf.js (aka protobufjs) 6.10.0 through 7.x before 7.2.5 allows Prototype Pollution, a different vulnerability than CVE-2022-25878. A user-controlled protobuf message can be used by an attacker to pollute the prototype of Object.prototype by adding and overwriting its data and functions. Exploitation can involve: (1) using the function parse to parse protobuf messages on the fly, (2) loading .proto files by using load/loadSync functions, or (3) providing untrusted input to the functions ReflectionObject.setParsedOption and util.setProperty.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | protobufjs | ≥ 7.0.0&&< 7.2.5 | 7.2.5 |
| 📦npm | protobufjs | ≥ 6.10.0&&< 6.11.4 | 6.11.4 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for protobufjs. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update protobufjs to 7.2.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-36665 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 pinpoints whether CVE-2023-36665 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2023-36665. 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-2023-36665 in your dependencies?
O3 detects CVE-2023-36665 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.