CVE-2026-44290

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.

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.

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.

CVE-2026-44290 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (7.5.6, 8.0.2); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-44290? CVE-2026-44290 is a high-severity security vulnerability in protobufjs (npm), affecting versions <= 7.5.5. It is fixed in 7.5.6, 8.0.2.
2. How severe is CVE-2026-44290? CVE-2026-44290 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of protobufjs are affected by CVE-2026-44290? protobufjs (npm) versions <= 7.5.5 is affected.
4. Is there a fix for CVE-2026-44290? Yes. CVE-2026-44290 is fixed in 7.5.6, 8.0.2. Upgrade to this version or later.
5. Is CVE-2026-44290 exploitable, and should I be worried? Whether CVE-2026-44290 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-44290 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-44290?
   • Upgrade protobufjs to 7.5.6 or later
   • Upgrade protobufjs to 8.0.2 or later