{
  "schema_version": "1.4.0",
  "id": "GHSA-wmg4-8cp2-hpg9",
  "modified": "2024-09-24T15:43:44Z",
  "published": "2021-04-19T14:54:04Z",
  "aliases": [
    "CVE-2021-29430"
  ],
  "summary": "Sydent vulnerable to denial of service attack via memory exhaustion",
  "details": "### Impact\n\nSydent does not limit the size of requests it receives from HTTP clients. A malicious user could send an HTTP request with a very large body, leading to disk space exhaustion and denial of service.\n\nSydent also does not limit response size for requests it makes to remote Matrix homeservers. A malicious homeserver could return a very large response, again leading to memory exhaustion and denial of service.\n\nThis affects any server which accepts registration requests from untrusted clients.\n\n### Patches\n\nPatched by 89071a1, 0523511, f56eee3.\n\n### Workarounds\n\nRequest sizes can be limited in an HTTP reverse-proxy.\n\nThere are no known workarounds for the problem with overlarge responses.\n\n### For more information\n\nIf you have any questions or comments about this advisory, email us at security@matrix.org.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
    },
    {
      "type": "CVSS_V4",
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "matrix-sydent"
      },
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.3.0"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/sydent/security/advisories/GHSA-wmg4-8cp2-hpg9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-29430"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/sydent/commit/0523511d2fb40f2738f8a8549868f44b96e5dab7"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/sydent/commit/89071a1a754c69a50deac89e6bb74002d4cda19d"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/sydent/commit/f56eee315b6c44fdd9f6aa785cc2ec744a594428"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/matrix-org/sydent"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/sydent/releases/tag/v2.3.0"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/matrix-sydent/PYSEC-2021-21.yaml"
    },
    {
      "type": "WEB",
      "url": "https://pypi.org/project/matrix-sydent"
    }
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-20",
      "CWE-400",
      "CWE-770"
    ],
    "severity": "HIGH",
    "github_reviewed": true,
    "github_reviewed_at": "2021-04-15T20:49:34Z",
    "nvd_published_at": "2021-04-15T21:15:00Z"
  }
}