What is the CVSS score of CVE-2026-44290?

CVE-2026-44290 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.0%.

Which versions of protobufjs are affected by CVE-2026-44290?

Prototype pollution vulnerability in protobufjs (CVE-2026-44290) enables denial of service attacks against applications that parse untrusted protobuf schemas or JSON descriptors, allowing attackers…. A patch is available.

How to fix or mitigate CVE-2026-44290?

Within 24 hours: Identify all applications using protobufjs and determine whether they parse schemas from untrusted sources (user uploads, external APIs, dynamic configuration) versus only decoding messages with hardcoded schemas. Within 7 days: For affected applications, upgrade protobufjs to v7.5.6 or v8.0.2 (depending on your current major version). Within 30 days: Review schema ingestion workflows; implement schema validation, allowlisting, and source verification to reduce exposure to untrusted schema inputs.

protobufjs CVE-2026-44290

HIGH

Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution) (CWE-1321)

2026-05-12 https://github.com/protobufjs/protobuf.js

GHSA-jvwf-75h9-cwgg

Denial Of Service RCE Prototype Pollution

7.5

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

7.5 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

Source Code Evidence Fetched

May 12, 2026 - 16:00 vuln.today

Analysis Generated

May 12, 2026 - 16:00 vuln.today

CVE Published

May 12, 2026 - 15:01 nvd

HIGH 7.5

Blast Radius

ecosystem impact

† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth

1,242 npm packages depend on protobufjs (72 direct, 1,171 indirect)

Ecosystem-wide dependent count for version 8.0.0.

DescriptionGitHub Advisory

Summary

protobufjs allowed certain schema option paths to traverse through inherited object properties while applying options. A crafted protobuf schema or JSON descriptor could cause option handling to write to properties on global JavaScript constructors, corrupting process-wide built-in functionality.

Impact

An attacker who can provide or influence protobuf schemas or JSON descriptors may be able to corrupt built-in process state in a way that causes subsequent application code or protobufjs code to fail. This can result in a persistent denial of service for the lifetime of the affected process.

This issue affects applications that parse or load protobuf schemas or descriptors from untrusted sources. Applications that use bundled, generated, or otherwise trusted schemas to decode untrusted protobuf message payloads are not directly affected.

The issue is not known to allow code execution by itself.

Preconditions

The application must allow an attacker to control or influence a protobuf schema or JSON descriptor.
The application must parse or load that schema through protobufjs reflection APIs such as parse, Root.load, Root.loadSync, or Root.fromJSON.
The crafted input must contain option paths that reach unsafe inherited properties during option processing.

Workarounds

Do not parse or load protobuf schemas or JSON descriptors from untrusted sources with affected versions. If untrusted schemas must be accepted, validate or reject option names containing unsafe property path components before loading them, and run schema processing in an isolated process.

AnalysisAI

Prototype pollution in protobufjs allows denial of service through corrupted JavaScript built-ins when parsing untrusted schemas. Attackers who control protobuf schemas or JSON descriptors can write to inherited object properties on global constructors, causing process-wide state corruption that persists until restart. CVSS 7.5 (High) with network vector and no authentication required, but real-world risk is limited to applications parsing schemas from untrusted sources-applications only decoding untrusted message payloads with trusted schemas are not affected. Vendor-released patches available: v7.5.6 and v8.0.2. No active exploitation confirmed (not in CISA KEV), and no public exploit code identified at time of analysis.

Technical ContextAI

This vulnerability affects protobufjs (pkg:npm/protobufjs), a JavaScript implementation of Protocol Buffers for serialization. The issue stems from CWE-1321 (Improperly Controlled Modification of Object Prototype Attributes, commonly called prototype pollution). During schema option processing via reflection APIs (parse, Root.load, Root.loadSync, Root.fromJSON), protobufjs failed to sanitize option paths, allowing traversal through JavaScript's prototype chain. Crafted schema option paths could reach inherited properties like __proto__ or constructor.prototype, enabling writes to global constructors (Object, Array, etc.). This corrupts process-wide built-in functionality rather than application-specific state. The vulnerability exists in protobufjs <=7.5.5 and versions 8.0.0-8.0.1, affecting Node.js and browser environments using the library for dynamic schema parsing.

RemediationAI

Upgrade to patched versions immediately: v7.5.6 for 7.x users or v8.0.2 for 8.x users per vendor releases at https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v7.5.6 and https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v8.0.2. The v7.5.6 release backports input hardening and CLI fixes (commit 75392ea). If immediate patching is not feasible, implement compensating controls: (1) Reject all protobuf schemas and JSON descriptors from untrusted sources-only load schemas from version-controlled, reviewed sources bundled with the application; (2) If untrusted schema input is unavoidable, validate option paths before parsing by rejecting schemas containing unsafe property names like __proto__, constructor, or prototype in option paths; (3) Isolate schema processing in a separate Node.js worker process with restricted permissions and restart it after each schema load to contain corruption; this adds significant performance overhead and complexity. Applications that only decode untrusted protobuf messages using pre-compiled or bundled schemas do not require emergency action, but should still upgrade during normal maintenance cycles to eliminate the attack vector entirely.