Vulnerability-Lookup

PYSEC-2026-845

Vulnerability from pysec - Published: 2026-07-06 08:03 - Updated: 2026-07-06 08:03

Details

Matrix Synapse before 0.33.3.1 and 0.33.2.1 allows remote attackers to spoof events and possibly have unspecified other impacts by leveraging improper transaction and event signature validation.

Severity

8.8 (High)


                  
                    CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Impacted products

Name	purl
matrix-synapse	pkg:pypi/matrix-synapse

Aliases

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "matrix-synapse",
        "purl": "pkg:pypi/matrix-synapse"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.33.2.1"
            },
            {
              "introduced": "0.33.3"
            },
            {
              "fixed": "0.33.3.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2018-16515",
    "GHSA-fmvh-rvq5-hhjx"
  ],
  "details": "Matrix Synapse before 0.33.3.1 and 0.33.2.1 allows remote attackers to spoof events and possibly have unspecified other impacts by leveraging improper transaction and event signature validation.",
  "id": "PYSEC-2026-845",
  "modified": "2026-07-06T08:03:21.195845Z",
  "published": "2026-07-06T08:03:21.195845Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2018-16515"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/synapse/issues/3796#event-1833126269"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/synapse/commit/5bf8bc79ebc22c61968f2eb487714813fccbdb9b"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/synapse/commit/804dd41e18c449e711e443398b95c9f6c68b6fa2"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/synapse/commit/a5a0bf5cf71caed3c4e3677d2bce667c147dadfc"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/synapse/commit/c127c8d0421f0228a46ebbe280c9537e8d8ea42b"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/matrix-org/synapse"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IRW7YR2H3ASUSYX4AO4KMY3FNVDNYW3P"
    },
    {
      "type": "WEB",
      "url": "https://matrix.org/blog/2018/09/06/critical-security-update-synapse-0-33-3-1"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/matrix-synapse"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-fmvh-rvq5-hhjx"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Matrix Synapse Improper Signature Validation"
}

CVE-2018-16515 (GCVE-0-2018-16515)

Vulnerability from cvelistv5 – Published: 2018-09-18 21:00 – Updated: 2024-08-05 10:24

Summary

Matrix Synapse before 0.33.3.1 allows remote attackers to spoof events and possibly have unspecified other impacts by leveraging improper transaction and event signature validation.

Severity

No CVSS data available.

CWE

Assigner

mitre CNA under the mitre root

CNA scorecard E 29/100 over 2330 records in the last 180 days details

References

3 references

URL	Tags
https://github.com/matrix-org/synapse/issues/3796…	x_refsource_CONFIRM
https://lists.fedoraproject.org/archives/list/pac…	vendor-advisoryx_refsource_FEDORA
https://matrix.org/blog/2018/09/06/critical-secur…	x_refsource_CONFIRM

Date Public

2018-09-05 00:00

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-05T10:24:32.888Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_refsource_CONFIRM",
              "x_transferred"
            ],
            "url": "https://github.com/matrix-org/synapse/issues/3796#event-1833126269"
          },
          {
            "name": "FEDORA-2018-6db422c637",
            "tags": [
              "vendor-advisory",
              "x_refsource_FEDORA",
              "x_transferred"
            ],
            "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IRW7YR2H3ASUSYX4AO4KMY3FNVDNYW3P/"
          },
          {
            "tags": [
              "x_refsource_CONFIRM",
              "x_transferred"
            ],
            "url": "https://matrix.org/blog/2018/09/06/critical-security-update-synapse-0-33-3-1/"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "datePublic": "2018-09-05T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "Matrix Synapse before 0.33.3.1 allows remote attackers to spoof events and possibly have unspecified other impacts by leveraging improper transaction and event signature validation."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "n/a",
              "lang": "en",
              "type": "text"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2018-09-18T20:57:01.000Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/matrix-org/synapse/issues/3796#event-1833126269"
        },
        {
          "name": "FEDORA-2018-6db422c637",
          "tags": [
            "vendor-advisory",
            "x_refsource_FEDORA"
          ],
          "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IRW7YR2H3ASUSYX4AO4KMY3FNVDNYW3P/"
        },
        {
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://matrix.org/blog/2018/09/06/critical-security-update-synapse-0-33-3-1/"
        }
      ],
      "x_legacyV4Record": {
        "CVE_data_meta": {
          "ASSIGNER": "cve@mitre.org",
          "ID": "CVE-2018-16515",
          "STATE": "PUBLIC"
        },
        "affects": {
          "vendor": {
            "vendor_data": [
              {
                "product": {
                  "product_data": [
                    {
                      "product_name": "n/a",
                      "version": {
                        "version_data": [
                          {
                            "version_value": "n/a"
                          }
                        ]
                      }
                    }
                  ]
                },
                "vendor_name": "n/a"
              }
            ]
          }
        },
        "data_format": "MITRE",
        "data_type": "CVE",
        "data_version": "4.0",
        "description": {
          "description_data": [
            {
              "lang": "eng",
              "value": "Matrix Synapse before 0.33.3.1 allows remote attackers to spoof events and possibly have unspecified other impacts by leveraging improper transaction and event signature validation."
            }
          ]
        },
        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "eng",
                  "value": "n/a"
                }
              ]
            }
          ]
        },
        "references": {
          "reference_data": [
            {
              "name": "https://github.com/matrix-org/synapse/issues/3796#event-1833126269",
              "refsource": "CONFIRM",
              "url": "https://github.com/matrix-org/synapse/issues/3796#event-1833126269"
            },
            {
              "name": "FEDORA-2018-6db422c637",
              "refsource": "FEDORA",
              "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IRW7YR2H3ASUSYX4AO4KMY3FNVDNYW3P/"
            },
            {
              "name": "https://matrix.org/blog/2018/09/06/critical-security-update-synapse-0-33-3-1/",
              "refsource": "CONFIRM",
              "url": "https://matrix.org/blog/2018/09/06/critical-security-update-synapse-0-33-3-1/"
            }
          ]
        }
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2018-16515",
    "datePublished": "2018-09-18T21:00:00.000Z",
    "dateReserved": "2018-09-05T00:00:00.000Z",
    "dateUpdated": "2024-08-05T10:24:32.888Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}

GHSA-FMVH-RVQ5-HHJX

Vulnerability from github – Published: 2022-05-13 01:50 – Updated: 2023-10-06 17:19

Summary

Matrix Synapse Improper Signature Validation

Details

Matrix Synapse before 0.33.3.1 and 0.33.2.1 allows remote attackers to spoof events and possibly have unspecified other impacts by leveraging improper transaction and event signature validation.

Severity

8.8 (High)


                  
                    CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "matrix-synapse"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.33.3"
            },
            {
              "fixed": "0.33.3.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "matrix-synapse"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.33.2.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2018-16515"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-347"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2023-07-24T20:04:34Z",
    "nvd_published_at": "2018-09-18T21:29:00Z",
    "severity": "HIGH"
  },
  "details": "Matrix Synapse before 0.33.3.1 and 0.33.2.1 allows remote attackers to spoof events and possibly have unspecified other impacts by leveraging improper transaction and event signature validation.",
  "id": "GHSA-fmvh-rvq5-hhjx",
  "modified": "2023-10-06T17:19:32Z",
  "published": "2022-05-13T01:50:21Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2018-16515"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/synapse/issues/3796#event-1833126269"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/synapse/commit/5bf8bc79ebc22c61968f2eb487714813fccbdb9b"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/synapse/commit/804dd41e18c449e711e443398b95c9f6c68b6fa2"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/synapse/commit/a5a0bf5cf71caed3c4e3677d2bce667c147dadfc"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/synapse/commit/c127c8d0421f0228a46ebbe280c9537e8d8ea42b"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/matrix-org/synapse"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IRW7YR2H3ASUSYX4AO4KMY3FNVDNYW3P"
    },
    {
      "type": "WEB",
      "url": "https://matrix.org/blog/2018/09/06/critical-security-update-synapse-0-33-3-1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Matrix Synapse Improper Signature Validation"
}

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

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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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PYSEC-2026-845

CVE-2018-16515 (GCVE-0-2018-16515)

GHSA-FMVH-RVQ5-HHJX

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Sightings

Nomenclature

Vulnerability timeline

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