CriticalPublic exploit

Arbitrary Code Execution in protobufjs via crafted type fields

IdentifiersCVE-2026-41242CWE-94· Improper Control of Generation of…

CVE-2026-41242 affects protobufjs, which compiles Protocol Buffers definitions into JavaScript functions at runtime. In versions prior to 8.0.1 and 7.5.5, an attacker can inject arbitrary JavaScript code into the "type" fields of protobuf definitions or attacker-controlled JSON descriptors. When the application later decodes an object using the malicious definition, protobufjs reaches the generated-code path and executes the injected code in the context of the affected Node.js or JavaScript process. The issue is an unsafe code generation / code injection flaw in schema handling and is classified as CWE-94.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation results in arbitrary JavaScript code execution within the security context of the application using protobufjs. This can lead to full compromise of the affected process, including theft or modification of application data, execution of further system commands depending on runtime privileges, service disruption, and potential lateral movement or compromise of connected systems reachable from the application.

Mitigation

If you can’t patch tonight, do this now.

Do not load protobuf definitions or JSON descriptors from untrusted sources while running affected versions. Where untrusted schemas cannot be avoided, strictly validate and constrain schema content before loading, especially metadata fields such as "type", and process such schemas in an isolated or sandboxed environment with minimal privileges. Restrict who can supply or modify protobuf schema inputs and avoid exposing reflection or descriptor-loading paths to untrusted users.

Remediation

Patch, then assume compromise.

Upgrade protobufjs to a fixed release. The issue is patched in version 7.5.5 for the 7.x branch and 8.0.1 for the 8.x branch. Replace vulnerable versions prior to 7.5.5 or prior to 8.0.1 with the appropriate patched version and redeploy applications that load or process protobuf schemas or JSON descriptors.

PUBLIC EXPLOITS

Exploits

No valid public exploits. Mallory filtered out 1 candidate as fakes, detection scripts, or README-only repos.

VALID 0 / 1 TOTALView more in app

All candidate exploits were filtered out by Mallory's validation.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

Protobufjs ProjectProtobufjsapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

4 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

4 SOURCESView more in app

cvefeed high severityNews

Apr 18, 2026

CVE-2026-41242 - protobufjs has an arbitrary code execution issue

An arbitrary code injection and execution vulnerability in protobufjs affecting versions prior to 8.0.1 and 7.5.5, where malicious code can be injected via the "type" fields of protobuf definitions and executed during object decoding.

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity3