CVE-2026-54270

The record

protobufjs compiles protobuf definitions into JavaScript (JS) functions. From 8.2.0 to 8.4.2, protobufjs preserved unknown wire elements in message.$unknowns and did not provide a decode-time option to discard unknown fields before retaining them. A crafted protobuf payload containing many unknown fields could therefore cause a decoded message to retain substantially more memory than the input size would suggest, even when unknown-field round-tripping is not needed. protobufjs 8.5.0 added the relevant decode-time options, allowing applications that decode untrusted protobuf data to disable unknown-field retention during decode. protobufjs 8.6.2 flips the default so unknown fields are discarded unless explicitly opted into.

Affected packages

Related vulnerabilities

• GHSA-94rc-8x27-4472 protobufjs: Memory amplification from preserved unknown fields in binary decode Same vulnerability
• CVE-2026-54269 protobufjs compiles protobuf definitions into JavaScript (JS) functions. Also affects protobufjs
• CVE-2026-48712 protobufjs compiles protobuf definitions into JavaScript (JS) functions. Also affects protobufjs
• GHSA-wcpc-wj8m-hjx6 protobufjs: Denial of service through unbounded Any expansion during JSON conversion Also affects protobufjs
• GHSA-f38q-mgvj-vph7 protobufjs : Schema-derived names can shadow runtime-significant properties Also affects protobufjs
• GHSA-jggg-4jg4-v7c6 protobufjs: Denial of Service via unbounded recursive JSON descriptor expansion Also affects protobufjs
• CVE-2026-45740 protobufjs compiles protobuf definitions into JavaScript (JS) functions. Also affects protobufjs
• CVE-2026-44294 protobufjs compiles protobuf definitions into JavaScript (JS) functions. Also affects protobufjs