CVE-2026-59876
Published:July 08, 2026
Updated:August 04, 2026
protobufjs compiles protobuf definitions into JavaScript (JS) functions. From 8.2.0 until 8.6.5, the protobufjs Text Format extension parsed string-keyed map entries using ordinary property assignment, allowing a map entry with key proto to change the prototype of the returned map object instead of creating an own map entry in protobufjs/ext/textformat. This issue is fixed in version 8.6.5.
Affected Packages
https://github.com/protobufjs/protobuf.js.git (GITHUB):
Affected version(s) >=protobufjs-v8.2.0 <protobufjs-v8.6.5Fix Suggestion:
Update to version protobufjs-v8.6.5protobufjs (NPM):
Affected version(s) >=8.2.0 <8.6.5Fix Suggestion:
Update to version 8.6.5Additional Notes
The description of this vulnerability differs from MITRE.
Related Resources (7)
Do you need more information?
Contact UsCVSS v4
Base Score:
6.3
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
LOW
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
4.8
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Weakness Type (CWE)
Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
EPSS
Base Score:
0.22