{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "0ADDA491-E534-4DFB-856F-9D07F38F3A92",
              "versionEndExcluding": "4.3.18",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "9BAA2A25-EE70-4B9F-8848-2CCE9C243077",
              "versionEndExcluding": "4.4.12",
              "versionStartIncluding": "4.4.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "71845808-53CF-46D1-9A12-F14F1BAED488",
              "versionEndExcluding": "4.5.5",
              "versionStartIncluding": "4.5.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.5.5, 4.4.12, and 4.3.18, the server does not enforce a maximum length for the names of lists or filters, or for filter keywords, allowing any user to set an arbitrarily long string as the name or keyword. Any local user can abuse the list or filter fields to cause disproportionate storage and computing resource usage. They can additionally cause their own web interface to be unusable, although they must intentionally do this to themselves or unknowingly approve a malicious API client. Mastodon versions v4.5.5, v4.4.12, v4.3.18 are patched."
    },
    {
      "lang": "es",
      "value": "Mastodon es un servidor de red social gratuito, de c\u00f3digo abierto, basado en ActivityPub. Antes de las versiones 4.5.5, 4.4.12 y 4.3.18, el servidor no aplica una longitud m\u00e1xima para los nombres de listas o filtros, ni para las palabras clave de filtro, permitiendo a cualquier usuario establecer una cadena arbitrariamente larga como nombre o palabra clave. Cualquier usuario local puede abusar de los campos de lista o filtro para causar un uso desproporcionado de los recursos de almacenamiento y computaci\u00f3n. Adicionalmente, pueden hacer que su propia interfaz web sea inutilizable, aunque deben hacerlo intencionalmente a s\u00ed mismos o aprobar sin saberlo un cliente API malicioso. Las versiones de Mastodon v4.5.5, v4.4.12, v4.3.18 est\u00e1n parcheadas."
    }
  ],
  "id": "CVE-2026-23963",
  "lastModified": "2026-02-02T20:27:15.387",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "LOW",
          "baseScore": 4.3,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 1.4,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      },
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-01-22T03:15:46.550",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Release Notes"
      ],
      "url": "https://github.com/mastodon/mastodon/releases/tag/v4.3.18"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Release Notes"
      ],
      "url": "https://github.com/mastodon/mastodon/releases/tag/v4.4.12"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Release Notes"
      ],
      "url": "https://github.com/mastodon/mastodon/releases/tag/v4.5.5"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://github.com/mastodon/mastodon/security/advisories/GHSA-6x3w-9g92-gvf3"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}