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protobuf.js: Denial of service from crafted field names in generated code

Moderate severity GitHub Reviewed Published May 12, 2026 in protobufjs/protobuf.js • Updated May 14, 2026

Package

npm protobufjs (npm)

Affected versions

<= 7.5.5
>= 8.0.0, <= 8.0.1

Patched versions

7.5.6
8.0.2

Description

Summary

protobufjs generated JavaScript property accessors from schema-controlled field and oneof names. Certain control characters in field names were not escaped before being embedded into generated function bodies. A crafted schema or JSON descriptor could therefore cause generated encode, decode, verify, or conversion functions to fail during compilation.

Impact

An attacker who can provide or influence a protobuf schema or JSON descriptor may be able to make affected message types unusable by causing protobufjs runtime code generation to throw a syntax error.

This is a denial of service issue for applications that load untrusted schemas or descriptors. Applications that only use trusted, application-defined schemas are not directly affected by this issue.

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 crafted input must define a field name containing control characters that reach generated JavaScript property access.
  • The application must perform an operation that triggers protobufjs code generation for the affected type, such as encode, decode, verify, fromObject, or toObject.

Workarounds

Do not load protobuf schemas or JSON descriptors from untrusted sources with affected versions. If untrusted schemas must be accepted, validate field names before loading them and reject names containing control characters.

References

@dcodeIO dcodeIO published to protobufjs/protobuf.js May 12, 2026
Published to the GitHub Advisory Database May 12, 2026
Reviewed May 12, 2026
Published by the National Vulnerability Database May 13, 2026
Last updated May 14, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(36th percentile)

Weaknesses

Improper Input Validation

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. Learn more on MITRE.

CVE ID

CVE-2026-44294

GHSA ID

GHSA-2pr8-phx7-x9h3

Credits

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