How severe is CVE-2026-41242?

No CVSS score has been assigned to CVE-2026-41242 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-41242?

CVE-2026-41242 affects the following packages: protobufjs (npm), protobufjs (npm), protobufjs (npm). Ecosystems affected: npm.

How do I fix CVE-2026-41242?

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.

How do I detect CVE-2026-41242 in my npm dependencies?

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.

How do I mitigate CVE-2026-41242 if there is no patch (or I can't update yet)?

Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Is CVE-2026-41242 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-41242 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-41242?

CVE-2026-41242 has an EPSS (Exploit Prediction Scoring System) score of 0.8%, placing it in the 56th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-41242?

CVE-2026-41242 is classified as Code Injection (CWE-94). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-41242 published, and has it been updated?

CVE-2026-41242 was published on April 18, 2026 and was last updated on November 5, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2026-41242 — protobufjs

Fix: protobufjs/protobuf.js@086916b

CVE-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

Also known asGHSA-xq3m-2v4x-88gg

Published

Apr 18, 2026

Updated

Nov 5, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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

via FIRST.org ↗

0.8%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs56th percentile — riskier than 56% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

3 pkgs affected

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.

6Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

protobufjsnpm

123.4Mdownloads / week

Description

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

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`protobufjs`	≥ 8.0.0&&< 8.0.1	8.0.1`npm install protobufjs@8.0.1`
📦npm	`protobufjs`	≥ 7.0.0&&< 7.5.5	7.5.5`npm install protobufjs@7.5.5`
📦npm	`protobufjs`	all versions	6.11.6`npm install protobufjs@6.11.6`

Affected Products

1 product · 2 configurations

Application

protobufjsprotobufjs_project

< 7.5.5

1 version

8.0.0

Detection & mitigation playbook

Open-source dependency

Detect
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
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

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.

Red HatImportant

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…

Workaround published by Red Hat

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Source: Red Hat security advisory for CVE-2026-41242 (CC BY 4.0)

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 AI 3.3	`rhoai/odh-mod-arch-maas-rhel9:1790128949`	RHSA-2026:73987
Red Hat OpenShift Dev Spaces 3.30	`devspaces/code-rhel9:1787762793`	RHSA-2026:62260

Frequently Asked Questions

## 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

O3 Security · Impact-Aware SCA

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