CVE-2026-41242 — protobufjs
Fix: protobufjs/protobuf.js@535df44CVE-2026-41242 is a Code Injection vulnerability in protobufjs. A fix is available for protobufjs — see the affected versions and patch details below.
protobufjs has an arbitrary code execution issue
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-41242.
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.
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 execute generated JavaScript code derived from protobuf schema metadata. When loading a crafted JSON descriptor, schema-controlled type names and type references could reach runtime code generation without sufficient validation.
Impact
An attacker who can provide a malicious protobuf definition or JSON descriptor to an application may be able to execute arbitrary JavaScript in the context of the process using protobufjs.
This requires control over the protobuf schema or descriptor being loaded. Applications that only decode messages using trusted, application-defined schemas are not directly affected by this issue.
Preconditions
- The application must allow an attacker to control or influence a protobuf definition or JSON descriptor.
- The application must load that definition through protobufjs reflection APIs such as descriptor loading.
- The affected generated-code path must be reached, for example by performing an operation on the loaded type.
Workarounds
Do not load protobuf definitions or JSON descriptors from untrusted sources with affected versions. If untrusted schemas must be accepted, validate or restrict them before loading and run schema processing in an isolated environment.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | protobufjs | ≥ 8.0.0&&< 8.0.1 | 8.0.1npm install protobufjs@8.0.1 |
| 📦npm | protobufjs | all versions | 7.5.5npm install protobufjs@7.5.5 |
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 8.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-41242 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-2026-41242 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-41242. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This Important impact remote code execution vulnerability in protobufjs allows attackers to inject arbitrary code into the 'type' fields of protobuf definitions, which executes during object decoding. Red Hat products that process untrusted protobuf definitions using the affected library versions are at risk. Red Hat…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Developer Hub 1.8 | rhdh/rhdh-hub-rhel9:1779841586 | RHSA-2026:21338 |
| Red Hat Developer Hub 1.9 | rhdh/rhdh-hub-rhel9:1781187342 | RHSA-2026:26234 |
| Red Hat OpenShift AI 2.25 | rhoai/odh-dashboard-rhel9:1780467029 | RHSA-2026:24977 |
| Red Hat OpenShift AI 3.3 | rhoai/odh-mod-arch-maas-rhel9:1783082680 | RHSA-2026:37275 |
| Red Hat OpenShift Dev Spaces 3.30 | devspaces/code-rhel9:1787762793 | RHSA-2026:62260 |
Frequently Asked Questions
Is CVE-2026-41242 in your dependencies?
O3 Security finds CVE-2026-41242 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.