Vulnerability-Lookup

GHSA-GCX5-HXJ7-GPQQ

Vulnerability from github – Published: 2026-10-08 17:39 – Updated: 2026-10-08 17:39

Summary

msgpack5: Quadratic parsing in the streaming decoder

Details

Impact

The streaming decoder reparses an incomplete container from the beginning whenever another chunk arrives. A remote peer can split one valid MessagePack value across many small chunks, causing quadratic CPU usage and blocking the event loop.

Patches

The decoder now preserves incremental container state so completed elements are not parsed again when more input arrives.

Workarounds

Buffer each complete MessagePack value before decoding it, or limit the number of chunks accepted for a single value.

Severity

5.9 (Medium)


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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "msgpack5"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.1.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-107297"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-407"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-08T17:39:46Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nThe streaming decoder reparses an incomplete container from the beginning whenever another chunk arrives. A remote peer can split one valid MessagePack value across many small chunks, causing quadratic CPU usage and blocking the event loop.\n\n### Patches\n\nThe decoder now preserves incremental container state so completed elements are not parsed again when more input arrives.\n\n### Workarounds\n\nBuffer each complete MessagePack value before decoding it, or limit the number of chunks accepted for a single value.",
  "id": "GHSA-gcx5-hxj7-gpqq",
  "modified": "2026-10-08T17:39:46Z",
  "published": "2026-10-08T17:39:46Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/mcollina/msgpack5/security/advisories/GHSA-gcx5-hxj7-gpqq"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mcollina/msgpack5/commit/e4827641d3105e295cbbd56e9c5389978547eab4"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mcollina/msgpack5"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mcollina/msgpack5/releases/tag/v6.1.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "msgpack5: Quadratic parsing in the streaming decoder"
}

CVE-2026-107297 (GCVE-0-2026-107297)

Vulnerability from cvelistv5 – Published: 2026-10-08 17:07 – Updated: 2026-10-08 17:26

Title

msgpack5: Quadratic parsing in the streaming decoder

Summary

msgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, the streaming decoder reparses an incomplete array or map from the beginning whenever another chunk arrives. A remote peer can split one valid MessagePack container across many small chunks, causing completed elements to be decoded repeatedly, producing quadratic CPU use and blocking the event loop. This issue is fixed in version 6.1.0.

Severity

5.9 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-08 17:26 UTC

CWE

CWE-407 - Inefficient Algorithmic Complexity

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7712 records in the last 180 days details

References

3 references

URL	Tags
https://github.com/mcollina/msgpack5/security/adv…	x_refsource_CONFIRM
https://github.com/mcollina/msgpack5/commit/e4827…	x_refsource_MISC
https://github.com/mcollina/msgpack5/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
mcollina	msgpack5	Affected: < 6.1.0

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-107297",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-08T17:26:19.427864Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-08T17:26:27.457Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "msgpack5",
          "vendor": "mcollina",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 6.1.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "msgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, the streaming decoder reparses an incomplete array or map from the beginning whenever another chunk arrives. A remote peer can split one valid MessagePack container across many small chunks, causing completed elements to be decoded repeatedly, producing quadratic CPU use and blocking the event loop. This issue is fixed in version 6.1.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 5.9,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-407",
              "description": "CWE-407: Inefficient Algorithmic Complexity",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-08T17:07:03.740Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/mcollina/msgpack5/security/advisories/GHSA-gcx5-hxj7-gpqq",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/mcollina/msgpack5/security/advisories/GHSA-gcx5-hxj7-gpqq"
        },
        {
          "name": "https://github.com/mcollina/msgpack5/commit/e4827641d3105e295cbbd56e9c5389978547eab4",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/mcollina/msgpack5/commit/e4827641d3105e295cbbd56e9c5389978547eab4"
        },
        {
          "name": "https://github.com/mcollina/msgpack5/releases/tag/v6.1.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/mcollina/msgpack5/releases/tag/v6.1.0"
        }
      ],
      "source": {
        "advisory": "GHSA-gcx5-hxj7-gpqq",
        "discovery": "UNKNOWN"
      },
      "title": "msgpack5: Quadratic parsing in the streaming decoder"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-107297",
    "datePublished": "2026-10-08T17:07:03.740Z",
    "dateReserved": "2026-10-07T15:53:23.587Z",
    "dateUpdated": "2026-10-08T17:26:27.457Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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