CVE-2026-92707 (GCVE-0-2026-92707)

Vulnerability from cvelistv5 – Published: 2026-10-15 18:35 – Updated: 2026-10-15 20:12
VLAI
Title
MessagePack: Nested arrays can blow past buffer length limits
Summary
MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.303 and 3.1.9, deserializing attacker-controlled MessagePack data as System.Object through PrimitiveObjectFormatter can cause excessive memory allocation. The formatter allocates an object[] from each declared array length before the configured object-graph depth limit rejects the input, while nested array headers can reuse the same trailing unread bytes to satisfy per-header length validation. A comparatively small payload can therefore keep many large arrays alive at once. When an attacker can submit such data repeatedly, the allocations can cause severe managed-heap pressure, excessive garbage collection, process termination, or loss of service. Exposure requires an application to deserialize untrusted data through the affected formatter path and permit repeated attacker-controlled submissions, such as a reachable ASP.NET Core SignalR hub method with an object parameter and AddMessagePackProtocol() enabled. This issue is fixed in versions 2.5.303 and 3.1.9.
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 · CISA-ADP (v2.0.3)
Decision recorded 2026-10-15 20:10 UTC
CWE
  • CWE-1325 - Improperly Controlled Sequential Memory Allocation
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7994 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
MessagePack-CSharp MessagePack-CSharp Affected: < 2.5.303
Affected: >= 3.0.0, < 3.1.9
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-92707",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-15T20:10:28.719217Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-15T20:12:15.468Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "MessagePack-CSharp",
          "vendor": "MessagePack-CSharp",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.5.303"
            },
            {
              "status": "affected",
              "version": "\u003e= 3.0.0, \u003c 3.1.9"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.303 and 3.1.9, deserializing attacker-controlled MessagePack data as System.Object through PrimitiveObjectFormatter can cause excessive memory allocation. The formatter allocates an object[] from each declared array length before the configured object-graph depth limit rejects the input, while nested array headers can reuse the same trailing unread bytes to satisfy per-header length validation. A comparatively small payload can therefore keep many large arrays alive at once. When an attacker can submit such data repeatedly, the allocations can cause severe managed-heap pressure, excessive garbage collection, process termination, or loss of service. Exposure requires an application to deserialize untrusted data through the affected formatter path and permit repeated attacker-controlled submissions, such as a reachable ASP.NET Core SignalR hub method with an object parameter and AddMessagePackProtocol() enabled. This issue is fixed in versions 2.5.303 and 3.1.9."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-1325",
              "description": "CWE-1325: Improperly Controlled Sequential Memory Allocation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-15T18:35:49.074Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-qhrr-8q5h-9q3h",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-qhrr-8q5h-9q3h"
        },
        {
          "name": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/7fd78bbf3476e03beae8b0f7a521125525a8a64a",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/7fd78bbf3476e03beae8b0f7a521125525a8a64a"
        },
        {
          "name": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/95b63fca4f7097d3cac12d1a95286af4b4bbf02c",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/95b63fca4f7097d3cac12d1a95286af4b4bbf02c"
        },
        {
          "name": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/releases/tag/v2.5.303",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/releases/tag/v2.5.303"
        },
        {
          "name": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/releases/tag/v3.1.9",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/releases/tag/v3.1.9"
        }
      ],
      "source": {
        "advisory": "GHSA-qhrr-8q5h-9q3h",
        "discovery": "UNKNOWN"
      },
      "title": "MessagePack: Nested arrays can blow past buffer length limits"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-92707",
    "datePublished": "2026-10-15T18:35:49.074Z",
    "dateReserved": "2026-09-16T16:22:31.542Z",
    "dateUpdated": "2026-10-15T20:12:15.468Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-92707",
      "date": "2026-10-29",
      "epss": "0.00678",
      "percentile": "0.52237"
    },
    "microsoft_vex": {
      "current_release_date": "2026-10-15T07:00:00.000Z",
      "cve": "CVE-2026-92707",
      "id": "msrc_CVE-2026-92707",
      "initial_release_date": "2026-10-13T07:00:00.000Z",
      "product_status:fixed": "14",
      "product_status:known_affected": "14",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "MessagePack-CSharp Denial of Service Vulnerability",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-92707.json",
      "version": "2"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "MessagePack-CSharp",
                "vendor": "MessagePack-CSharp",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003c 2.5.303"
                  },
                  {
                    "status": "affected",
                    "version": "\u003e= 3.0.0, \u003c 3.1.9"
                  }
                ]
              }
            ],
            "source": "security-advisories@github.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.303 and 3.1.9, deserializing attacker-controlled MessagePack data as System.Object through PrimitiveObjectFormatter can cause excessive memory allocation. The formatter allocates an object[] from each declared array length before the configured object-graph depth limit rejects the input, while nested array headers can reuse the same trailing unread bytes to satisfy per-header length validation. A comparatively small payload can therefore keep many large arrays alive at once. When an attacker can submit such data repeatedly, the allocations can cause severe managed-heap pressure, excessive garbage collection, process termination, or loss of service. Exposure requires an application to deserialize untrusted data through the affected formatter path and permit repeated attacker-controlled submissions, such as a reachable ASP.NET Core SignalR hub method with an object parameter and AddMessagePackProtocol() enabled. This issue is fixed in versions 2.5.303 and 3.1.9."
          }
        ],
        "id": "CVE-2026-92707",
        "lastModified": "2026-10-16T16:00:33.533",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "LOW",
                "baseScore": 5.3,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 1.4,
              "source": "security-advisories@github.com",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-92707",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "yes"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-15T20:10:28.719217Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-10-15T19:17:48.703",
        "references": [
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/7fd78bbf3476e03beae8b0f7a521125525a8a64a"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/95b63fca4f7097d3cac12d1a95286af4b4bbf02c"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/releases/tag/v2.5.303"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/releases/tag/v3.1.9"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-qhrr-8q5h-9q3h"
          }
        ],
        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Awaiting Analysis",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-1325"
              }
            ],
            "source": "security-advisories@github.com",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-10-29T20:54:51+00:00",
      "cve": "CVE-2026-92707",
      "id": "CVE-2026-92707",
      "initial_release_date": "2026-10-13T17:00:00+00:00",
      "product_status:fixed": "1422",
      "product_status:known_not_affected": "3",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "dotnet10.0: dotnet8.0: dotnet9.0: dotnet: MessagePack: Nested arrays can blow past buffer length limits",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-92707.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-92707",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-10-15T20:10:28.719217Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-10-15T20:12:09.856Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "product": "MessagePack-CSharp",
              "vendor": "MessagePack-CSharp",
              "versions": [
                {
                  "status": "affected",
                  "version": "\u003c 2.5.303"
                },
                {
                  "status": "affected",
                  "version": "\u003e= 3.0.0, \u003c 3.1.9"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.303 and 3.1.9, deserializing attacker-controlled MessagePack data as System.Object through PrimitiveObjectFormatter can cause excessive memory allocation. The formatter allocates an object[] from each declared array length before the configured object-graph depth limit rejects the input, while nested array headers can reuse the same trailing unread bytes to satisfy per-header length validation. A comparatively small payload can therefore keep many large arrays alive at once. When an attacker can submit such data repeatedly, the allocations can cause severe managed-heap pressure, excessive garbage collection, process termination, or loss of service. Exposure requires an application to deserialize untrusted data through the affected formatter path and permit repeated attacker-controlled submissions, such as a reachable ASP.NET Core SignalR hub method with an object parameter and AddMessagePackProtocol() enabled. This issue is fixed in versions 2.5.303 and 3.1.9."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "LOW",
                "baseScore": 5.3,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
                "version": "3.1"
              }
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-1325",
                  "description": "CWE-1325: Improperly Controlled Sequential Memory Allocation",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-10-15T18:35:49.074Z",
            "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
            "shortName": "GitHub_M"
          },
          "references": [
            {
              "name": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-qhrr-8q5h-9q3h",
              "tags": [
                "x_refsource_CONFIRM"
              ],
              "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSA-qhrr-8q5h-9q3h"
            },
            {
              "name": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/7fd78bbf3476e03beae8b0f7a521125525a8a64a",
              "tags": [
                "x_refsource_MISC"
              ],
              "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/7fd78bbf3476e03beae8b0f7a521125525a8a64a"
            },
            {
              "name": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/95b63fca4f7097d3cac12d1a95286af4b4bbf02c",
              "tags": [
                "x_refsource_MISC"
              ],
              "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/commit/95b63fca4f7097d3cac12d1a95286af4b4bbf02c"
            },
            {
              "name": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/releases/tag/v2.5.303",
              "tags": [
                "x_refsource_MISC"
              ],
              "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/releases/tag/v2.5.303"
            },
            {
              "name": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/releases/tag/v3.1.9",
              "tags": [
                "x_refsource_MISC"
              ],
              "url": "https://github.com/MessagePack-CSharp/MessagePack-CSharp/releases/tag/v3.1.9"
            }
          ],
          "source": {
            "advisory": "GHSA-qhrr-8q5h-9q3h",
            "discovery": "UNKNOWN"
          },
          "title": "MessagePack: Nested arrays can blow past buffer length limits"
        }
      },
      "cveMetadata": {
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "assignerShortName": "GitHub_M",
        "cveId": "CVE-2026-92707",
        "datePublished": "2026-10-15T18:35:49.074Z",
        "dateReserved": "2026-09-16T16:22:31.542Z",
        "dateUpdated": "2026-10-15T20:12:15.468Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.