protobufjs: Denial of service through unbounded Any expansion during JSON conversion

## Summary protobufjs could recurse without a depth limit while converting decoded messages to plain objects or JSON. This affected generated `toObject()` conversion and the custom `google.protobuf.Any` JSON conversion path. A crafted protobuf binary payload containing deeply nested `Any` values could cause the JavaScript call stack to be exhausted during conversion to JSON. ## Impact An attacker who can provide protobuf binary data decoded by an application may be able to crash the process or otherwise cause message conversion to fail with a stack overflow. This affects applications that decode untrusted protobuf input containing `google.protobuf.Any` values and then convert decoded messages to JSON or plain objects with JSON conversion enabled, for example through `JSON.stringify(message)`, `Message#toJSON()`, or `Type.toObject(message, { json: true })`. Applications that only decode and re-encode protobuf binary data without converting decoded messages to JSON are not directly affected by this issue. ## Preconditions * The application must decode protobuf binary data influenced by an attacker. * The application schema must include `google.protobuf.Any`, and the referenced `type_url` must resolve to a message type in the loaded protobuf root. * The application must convert the decoded message to JSON or a plain object through an affected conversion path. * The crafted input must contain deeply nested `Any` values that are expanded during conversion. ## Workarounds Avoid converting untrusted protobuf messages containing `google.protobuf.Any` values to JSON with affected versions. If immediate upgrade is not possible, reject or limit messages with deeply nested `Any` payloads at an outer protocol boundary where feasible, avoid JSON conversion of untrusted `Any` values, or isolate message conversion in a process that can be safely restarted.

Source published

15 Jun 2026 17:30:15 UTC

Source modified

10 Sep 2026 03:51:09 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Publisher rating · HIGH