CVE-2026-54270: CWE-770: Allocation of Resources Without Limits or Throttling in protobufjs protobuf.js
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.
AI Analysis
Technical Summary
The vulnerability in protobuf.js (CVE-2026-54270) involves allocation of resources without limits or throttling (CWE-770). Specifically, versions 8.2.0 through 8.4.2 retain unknown protobuf fields in memory during decoding, which can lead to excessive memory usage when processing crafted payloads containing many unknown fields. Starting with version 8.5.0, options were introduced to disable retention of unknown fields, and in version 8.6.2 the default behavior was changed to discard unknown fields unless explicitly retained. This vulnerability affects the availability of systems using affected versions by increasing memory consumption but does not affect confidentiality or integrity.
Potential Impact
Excessive memory consumption can occur when processing specially crafted protobuf payloads with many unknown fields, potentially leading to denial of service due to resource exhaustion. There is no impact on confidentiality or integrity of data.
Mitigation Recommendations
Users should upgrade to protobuf.js version 8.5.0 or later, where options exist to disable retention of unknown fields, or preferably to version 8.6.2 or later, where the default behavior discards unknown fields unless explicitly retained. Patch status is not explicitly confirmed in the advisory, but upgrading to these versions effectively mitigates the issue.
CVE-2026-54270: CWE-770: Allocation of Resources Without Limits or Throttling in protobufjs protobuf.js
Description
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.
CVSS v3.1
Score 5.3medium
Affected software
pkg:npm/protobufjs/protobuf.jsRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in protobuf.js (CVE-2026-54270) involves allocation of resources without limits or throttling (CWE-770). Specifically, versions 8.2.0 through 8.4.2 retain unknown protobuf fields in memory during decoding, which can lead to excessive memory usage when processing crafted payloads containing many unknown fields. Starting with version 8.5.0, options were introduced to disable retention of unknown fields, and in version 8.6.2 the default behavior was changed to discard unknown fields unless explicitly retained. This vulnerability affects the availability of systems using affected versions by increasing memory consumption but does not affect confidentiality or integrity.
Potential Impact
Excessive memory consumption can occur when processing specially crafted protobuf payloads with many unknown fields, potentially leading to denial of service due to resource exhaustion. There is no impact on confidentiality or integrity of data.
Mitigation Recommendations
Users should upgrade to protobuf.js version 8.5.0 or later, where options exist to disable retention of unknown fields, or preferably to version 8.6.2 or later, where the default behavior discards unknown fields unless explicitly retained. Patch status is not explicitly confirmed in the advisory, but upgrading to these versions effectively mitigates the issue.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-12T17:13:32.279Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a39735beed863c81e39624c
Added to database: 06/22/2026, 17:39:39 UTC
Last enriched: 07/16/2026, 10:51:29 UTC
Last updated: 08/04/2026, 13:33:12 UTC
Views: 59
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