Vulnerability-Lookup

CVE-2026-54270 (GCVE-0-2026-54270)

Vulnerability from cvelistv5 – Published: 2026-06-22 16:19 – Updated: 2026-06-23 16:09

Title

protobufjs: Memory amplification from preserved unknown fields in binary decode

Summary

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.

Severity

5.3 (Medium)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-770 - Allocation of Resources Without Limits or Throttling

Assigner

GitHub_M

References

1 reference

URL	Tags
https://github.com/protobufjs/protobuf.js/securit…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
protobufjs	protobuf.js	Affected: >=8.2.0, < 8.5.0

Show details on NVD website

JSON

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GHSA-94RC-8X27-4472

Vulnerability from github – Published: 2026-06-15 20:13 – Updated: 2026-06-15 20:13

Summary

protobufjs: Memory amplification from preserved unknown fields in binary decode

Details

Summary

protobufjs 8.2.0 added support for preserving unknown fields encountered during binary decode. Affected versions 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.

Impact

An attacker who can provide protobuf binary data decoded by an application using affected protobufjs versions may be able to increase memory pressure by sending messages with many unknown fields. This can degrade availability or contribute to process termination in services that decode and retain attacker-controlled messages.

This issue affects applications that decode untrusted protobuf binary input and do not need unknown-field round-tripping. Applications that only decode trusted protobuf data, already enforce input-size/concurrency limits, or do not retain decoded messages beyond immediate processing are less directly affected.

Preconditions

The application must decode protobuf binary data influenced by an attacker.
The decoded schema must not define the attacker-selected field numbers, causing those fields to be treated as unknown.
The application must use a protobufjs version that preserves unknown fields but does not provide a decode-time discard option.
The decoded message, or enough decoded messages concurrently, must remain live long enough for retained unknown-field data to affect memory usage.

Workarounds

Upgrade to protobufjs 8.5.0 or newer and disable unknown-field preservation if not needed: Create a Reader, set reader.discardUnknown = true, and decode from that reader, or make this the default for subsequently created readers by setting Reader.discardUnknown = true. When upgrading to protobufjs 8.6.2 or newer, unknown fields are discarded by default unless opted into by setting discardUnknown = false.

Applications should also continue to enforce input-size, request concurrency, and request timeout limits at their transport or application boundary.

Severity

5.3 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 8.4.2"
      },
      "package": {
        "ecosystem": "npm",
        "name": "protobufjs"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.2.0"
            },
            {
              "fixed": "8.5.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-54270"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-15T20:13:28Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nprotobufjs 8.2.0 added support for preserving unknown fields encountered during binary decode. Affected versions preserved unknown wire elements in `message.$unknowns` and did not provide a decode-time option to discard unknown fields before retaining them.\n\nA 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.\n\n## Impact\n\nAn attacker who can provide protobuf binary data decoded by an application using affected protobufjs versions may be able to increase memory pressure by sending messages with many unknown fields. This can degrade availability or contribute to process termination in services that decode and retain attacker-controlled messages.\n\nThis issue affects applications that decode untrusted protobuf binary input and do not need unknown-field round-tripping. Applications that only decode trusted protobuf data, already enforce input-size/concurrency limits, or do not retain decoded messages beyond immediate processing are less directly affected.\n\n## Preconditions\n\n* The application must decode protobuf binary data influenced by an attacker.\n* The decoded schema must not define the attacker-selected field numbers, causing those fields to be treated as unknown.\n* The application must use a protobufjs version that preserves unknown fields but does not provide a decode-time discard option.\n* The decoded message, or enough decoded messages concurrently, must remain live long enough for retained unknown-field data to affect memory usage.\n\n## Workarounds\n\nUpgrade to protobufjs 8.5.0 or newer and disable unknown-field preservation if not needed: Create a `Reader`, set `reader.discardUnknown = true`, and decode from that reader, or make this the default for subsequently created readers by setting `Reader.discardUnknown = true`. When upgrading to protobufjs 8.6.2 or newer, unknown fields are discarded by default unless opted into by setting `discardUnknown = false`.\n\nApplications should also continue to enforce input-size, request concurrency, and request timeout limits at their transport or application boundary.",
  "id": "GHSA-94rc-8x27-4472",
  "modified": "2026-06-15T20:13:28Z",
  "published": "2026-06-15T20:13:28Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-94rc-8x27-4472"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/protobufjs/protobuf.js"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "protobufjs: Memory amplification from preserved unknown fields in binary decode"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

CVE-2026-54270 (GCVE-0-2026-54270)

GHSA-94RC-8X27-4472

Summary

Impact

Preconditions

Workarounds

Tags

Sightings

Nomenclature