CVE-2026-59877
MediumCVSS 5.3Exploitation Probability (EPSS)
Low risk29th percentile - higher than 29% of all known CVEs
Summary
A vulnerability in the protobufjs library allows infinite looping when parsing specially crafted .proto files. The lack of end-of-input checking when processing options causes parse, Root.load, or Root.loadSync to loop indefinitely.
Risk Assessment
An attacker can supply a malicious .proto file, leading to denial of service (DoS) by exhausting CPU and memory resources of the server or application using protobufjs.
Recommendation
Immediately update protobufjs to version 7.6.5 or 8.6.6 depending on the branch used. Before updating, validate all external .proto files.
Other vulnerabilities in protobufjs
See all- CVE-2026-41242Critical
A vulnerability in the protobufjs library allows arbitrary JavaScript code injection via 'type' fields in protobuf definitions. The code executes during object decoding. The issue is fixed in versions 8.0.1 and 7.5.5.
- CVE-2026-59876Medium
A vulnerability in the protobufjs library (versions 8.2.0 to 8.6.5) allows prototype pollution via parsing map entries in Text Format. An attacker can inject a map key named __proto__, which modifies the object prototype instead of creating a map entry.
- CVE-2026-54270Medium
Versions of protobufjs from 8.2.0 to 8.4.2 lacked options to discard unknown fields during decoding, which could lead to excessive memory usage by decoded messages. Version 8.5.0 introduced options to disable unknown field retention, and version 8.6.2 defaults to discarding unknown fields.
- CVE-2026-54269Medium
In versions prior to 8.6.0 and 7.6.3, protobufjs accepted certain schema-derived names that could collide with properties used by protobufjs runtime helpers. This could lead to deterministic exceptions or recursive calls in various operations related to decoding and serialization.
- CVE-2026-44293High
protobufjs before versions 7.5.6 and 8.0.2 generates JavaScript for the toObject function that may include an unsafe expression from a schema-controlled bytes field default value. A crafted descriptor can lead to arbitrary code execution.
- CVE-2026-44289High
Protobufjs before versions 7.5.6 and 8.0.2 lacks a depth limit when decoding nested protobuf data. A crafted binary payload can exhaust the JavaScript call stack, causing a crash.
Original NVD description (English source)
protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.6.5 and 8.6.6, protobufjs parsed option names by advancing through schema tokens until reaching an = token without checking for end of input, so a crafted .proto schema that opens an option declaration and ends prematurely can cause parse, Root.load, or Root.loadSync to loop indefinitely. This issue is fixed in versions 7.6.5 and 8.6.6.