CVE-2026-107298: msgpack5 Deeply Nested Input Can Exhaust Vulnerability

MODERATE
Advisory Identifier: GHSA-24ch-f2g6-9hhh
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CVSS 5.3
CWE-674
Published
Advisory Summary

CVE-2026-107298 is a MODERATE (CVSS 5.3) deeply nested input can exhaust vulnerability (CWE-674: Uncontrolled Recursion) affecting msgpack5 libraries in the npm ecosystem. The issue involves deeply nested input can exhaust the decoder stack. Remediation is available by upgrading affected packages to version 6.1.0.

CVE-2026-107298 at a Glance

CVE Identifier CVE-2026-107298
GHSA Identifier GHSA-24ch-f2g6-9hhh
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-674: Uncontrolled Recursion
Affected Product msgpack5
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:N/A:L).

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 None (I:N)
Availability Low (A:L)

How to Fix CVE-2026-107298

To remediate this vulnerability, upgrade all affected msgpack5 dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

msgpack5 fixed: 6.1.0 
npm install msgpack5@6.1.0
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 msgpack5

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-107298, inspect your project dependencies using npm:

npm ls msgpack5

Analyze the terminal output to locate any version of msgpack5 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 6.1.0), your application is affected.

Note: The npm ls msgpack5 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-674: Uncontrolled Recursion, where the product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack. In msgpack5, 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

### Impact The decoder has no nesting-depth limit for arrays and maps. An attacker who can provide MessagePack input can use deeply nested containers to exhaust the JavaScript call stack and interrupt the process or request handler. ### Patches The decoder now limits nesting depth to 100 by default and throws `Maximum decode depth exceeded`. Applications can configure the limit with the `maxDepth` option. ### Workarounds Reject deeply nested input before decoding, isolate decoding in a worker, or enforce a trusted schema with a bounded nesting depth.

CVE-2026-107298 Affected msgpack5 Versions

1 component(s)
Fixed Versions:
6.1.0
Product / Package Ecosystem Affected Versions Fixed Version
msgpack5
npm/msgpack5
npm
< 6.1.0
6.1.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/mcollina/msgpack5/security/advisories/GHSA-24ch-f2g6-9hhh
Security Fix Commit FIX COMMIT
https://github.com/mcollina/msgpack5/commit/1e2b5874e555dd7c99417f64788a03b0590bb102
msgpack5 Source Repository REPOSITORY
https://github.com/mcollina/msgpack5
msgpack5 Release RELEASE
https://github.com/mcollina/msgpack5/releases/tag/v6.1.0

Frequently Asked Questions

What is CVE-2026-107298?
CVE-2026-107298 is a security vulnerability in msgpack5 involving Deeply nested input can exhaust the decoder stack under CWE-674: Uncontrolled Recursion.
Which msgpack5 versions are affected?
Affected versions include releases prior to 6.1.0 across affected packages: msgpack5.
What version fixes CVE-2026-107298?
Upgrading to 6.1.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is msgpack5 affected?
Yes, msgpack5 is affected in releases prior to 6.1.0. Upgrade your dependency to 6.1.0 or later.
What is the CVSS score of CVE-2026-107298?
CVE-2026-107298 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:N/A:L.
What CWE is associated with CVE-2026-107298?
CVE-2026-107298 is classified under CWE-674: Uncontrolled Recursion (The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.).
How can I check npm dependencies for CVE-2026-107298?
Run the dependency tree command: 'npm ls msgpack5'. 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
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-24ch-f2g6-9hhh",
  "modified" : "2026-10-08T17:39:52Z",
  "published" : "2026-10-08T17:39:51Z",
  "aliases" : [ "CVE-2026-107298" ],
  "summary" : "msgpack5: Deeply nested input can exhaust the decoder stack",
  "details" : "### Impact\n\nThe decoder has no nesting-depth limit for arrays and maps. An attacker who can provide MessagePack input can use deeply nested containers to exhaust the JavaScript call stack and interrupt the process or request handler.\n\n### Patches\n\nThe decoder now limits nesting depth to 100 by default and throws `Maximum decode depth exceeded`. Applications can configure the limit with the `maxDepth` option.\n\n### Workarounds\n\nReject deeply nested input before decoding, isolate decoding in a worker, or enforce a trusted schema with a bounded nesting depth.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "msgpack5"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "6.1.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/mcollina/msgpack5/security/advisories/GHSA-24ch-f2g6-9hhh"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mcollina/msgpack5/commit/1e2b5874e555dd7c99417f64788a03b0590bb102"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mcollina/msgpack5"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mcollina/msgpack5/releases/tag/v6.1.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-674" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-10-08T17:39:51Z",
    "nvd_published_at" : null
  }
}