Medium [CVE-2026-54270] Denial of Service due to excessive memory consumption

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.

A flaw was found in protobufjs. A remote attacker could send a specially crafted protobuf payload containing numerous unknown fields.

This could cause the decoded message to retain substantially more memory than expected, leading to excessive memory consumption and potentially a Denial of Service (DoS) for applications processing untrusted protobuf data. Red Hat rates this issue as having Low impact for Red Hat Enterprise Linux AI bootc images.

Although protobufjs is present as a transitive dependency, the vulnerable parsing path is not exercised in normal product operation. Red Hat severity: Low — CVSS 5.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).