Vulnerabilities in pkg:npm/@protobufjs/utf8

PACKAGE
Advisory Identifier: GHSA-q6x5-8v7m-xcrf
Advisory Summary

CVE-2026-44288 is a MODERATE (CVSS 5.3) protobufjs has overlong utf-8 decoding vulnerability (CWE-176: Improper Handling of Unicode Encoding) affecting Protobufjs libraries in the npm ecosystem. The issue involves protobufjs has overlong utf-8 decoding. Remediation is available by upgrading affected packages to version 7.5.6, 8.0.2, 1.1.1.

1 Known Advisory Record(s)
Package Vulnerability Intelligence

pkg:npm/@protobufjs/utf8

1 Known Advisory Record(s)

Vulnerability advisories affecting package pkg:npm/@protobufjs/utf8. Select an advisory below to view technical details or fixes.

Advisory ID CVE / NVD Severity Summary
GHSA-q6x5-8v7m-xcrf CVE-2026-44288 MODERATE protobufjs has overlong UTF-8 decoding

CVE-2026-44288 at a Glance

CVE Identifier CVE-2026-44288
GHSA Identifier GHSA-q6x5-8v7m-xcrf
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-176: Improper Handling of Unicode Encoding
Affected Product Protobufjs
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 5.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-44288

To remediate this vulnerability, upgrade all affected Protobufjs dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

protobufjs fixed: 7.5.6
npm install protobufjs@7.5.6
protobufjs fixed: 8.0.2
npm install protobufjs@8.0.2
@protobufjs/utf8 fixed: 1.1.1
npm install @protobufjs/utf8@1.1.1
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

npm ls protobufjs

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-44288, inspect your project dependencies using npm:

npm ls protobufjs

Analyze the terminal output to locate any version of Protobufjs in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 7.5.6), your application is affected.

Note: The npm ls protobufjs command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-176: Improper Handling of Unicode Encoding, where the product does not properly handle when an input contains unicode encoding. In Protobufjs, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## Summary protobufjs includes a minimal UTF-8 decoder used in non-Node and fallback decoding paths. The affected decoder accepted overlong UTF-8 byte sequences and decoded them to their canonical characters instead of replacing them. The issue concerns overlong encodings and code points outside the Unicode range. protobufjs may still accept some non-strict UTF-8 input for compatibility, so applications should not rely on protobufjs as a general-purpose strict UTF-8 validator. ## Impact An attacker who can provide protobuf binary data decoded through the affected UTF-8 path may be able to bypass application-level checks that inspect raw bytes before protobuf string decoding. For example, bytes that do not contain certain ASCII characters could decode to strings containing those characters. The practical impact depends on downstream application validation and how decoded strings are used. Node.js Buffer-backed decoding paths are not directly affected when they use Node's native UTF-8 decoding. ## Preconditions - The application must decode protobuf binary data influenced by an attacker. - The affected protobuf string field must be decoded through protobufjs's minimal UTF-8 decoder rather than a native UTF-8 decoder. - The application must rely on byte-level filtering or validation before protobuf string decoding. - The decoded string must then be used in a security-sensitive context. ## Workarounds Avoid relying only on byte-level filtering before protobuf string decoding with affected versions. Validate decoded strings at the point where they are used, and prefer runtime paths that use native UTF-8 decoding where necessary.

CVE-2026-44288 Affected Protobufjs Versions

3 component(s)
Fixed Versions:
7.5.68.0.21.1.1
Product / Package Ecosystem Affected Versions Fixed Version
protobufjs
npm
< 7.5.6
7.5.6
protobufjs
npm
≥ 8.0.0
< 8.0.2
8.0.2
@protobufjs/utf8
npm
< 1.1.1
1.1.1

References

Frequently Asked Questions

What is CVE-2026-44288?
CVE-2026-44288 is a security vulnerability in Protobufjs involving protobufjs has overlong UTF-8 decoding under CWE-176: Improper Handling of Unicode Encoding.
Which Protobufjs versions are affected?
Affected versions include releases prior to 7.5.6, 8.0.2, 1.1.1 across affected packages: protobufjs, @protobufjs/utf8.
What version fixes CVE-2026-44288?
Upgrading to 7.5.6, 8.0.2, 1.1.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is protobufjs affected?
Yes, protobufjs is affected in releases prior to 7.5.6, 8.0.2. Upgrade your dependency to 7.5.6, 8.0.2 or later.
Is @protobufjs/utf8 affected?
Yes, @protobufjs/utf8 is affected in releases prior to 1.1.1. Upgrade your dependency to 1.1.1 or later.
What is the CVSS score of CVE-2026-44288?
CVE-2026-44288 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.
What CWE is associated with CVE-2026-44288?
CVE-2026-44288 is classified under CWE-176: Improper Handling of Unicode Encoding (The product does not properly handle when an input contains Unicode encoding.).
How can I check npm dependencies for CVE-2026-44288?
Run the dependency tree command: 'npm ls protobufjs'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-q6x5-8v7m-xcrf",
  "modified" : "2026-05-14T20:35:04Z",
  "published" : "2026-05-12T15:00:11Z",
  "aliases" : [ "CVE-2026-44288" ],
  "summary" : "protobufjs has overlong UTF-8 decoding",
  "details" : "## Summary\n\nprotobufjs includes a minimal UTF-8 decoder used in non-Node and fallback decoding paths. The affected decoder accepted overlong UTF-8 byte sequences and decoded them to their canonical characters instead of replacing them.\n\nThe issue concerns overlong encodings and code points outside the Unicode range. protobufjs may still accept some non-strict UTF-8 input for compatibility, so applications should not rely on protobufjs as a general-purpose strict UTF-8 validator.\n\n## Impact\n\nAn attacker who can provide protobuf binary data decoded through the affected UTF-8 path may be able to bypass application-level checks that inspect raw bytes before protobuf string decoding. For example, bytes that do not contain certain ASCII characters could decode to strings containing those characters.\n\nThe practical impact depends on downstream application validation and how decoded strings are used. Node.js Buffer-backed decoding paths are not directly affected when they use Node's native UTF-8 decoding.\n\n## Preconditions\n\n- The application must decode protobuf binary data influenced by an attacker.\n- The affected protobuf string field must be decoded through protobufjs's minimal UTF-8 decoder rather than a native UTF-8 decoder.\n- The application must rely on byte-level filtering or validation before protobuf string decoding.\n- The decoded string must then be used in a security-sensitive context.\n\n## Workarounds\n\nAvoid relying only on byte-level filtering before protobuf string decoding with affected versions. Validate decoded strings at the point where they are used, and prefer runtime paths that use native UTF-8 decoding where necessary.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "protobufjs"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "7.5.6"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 7.5.5"
    }
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "protobufjs"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "8.0.0"
      }, {
        "fixed" : "8.0.2"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 8.0.1"
    }
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@protobufjs/utf8"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.1.1"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.1.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-q6x5-8v7m-xcrf"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-44288"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/protobufjs/protobuf.js"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v7.5.6"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v8.0.2"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-176" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-12T15:00:11Z",
    "nvd_published_at" : "2026-05-13T16:16:55Z"
  }
}