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CVE-2021-22915

Status: ModifiedCritical (9.8)—

Nextcloud server before 19.0.11, 20.0.10, 21.0.2 is vulnerable to brute force attacks due to lack of inclusion of IPv6 subnets in rate-limiting considerations. This could potentially result in an attacker bypassing rate-limit controls such as the Nextcloud brute-force protection.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (2)

Fedoraproject — FedoraNextcloud — Nextcloud Server

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2021-22915",
  "cveTags": [],
  "metrics": {
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        "source": "nvd@nist.gov",
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          "baseScore": 5,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:P/I:N/A:N",
          "authentication": "NONE",
          "integrityImpact": "NONE",
          "accessComplexity": "LOW",
          "availabilityImpact": "NONE",
          "confidentialityImpact": "PARTIAL"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
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          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
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      "affectedData": [
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  "published": "2021-06-11T16:15:11.913",
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      "tags": [
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  "vulnStatus": "Modified",
  "weaknesses": [
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      "description": [
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    },
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      "lang": "es",
      "value": "Nextcloud server versiones anteriores a 19.0.11, 20.0.10 y 21.0.2, es vulnerable a ataques de fuerza bruta debido a una falta de inclusión de subredes IPv6 en las consideraciones de limitación de velocidad. Esto podría potencialmente resultar en que un atacante omita los controles de limitación de velocidad, como la protección de fuerza bruta de Nextcloud"
    }
  ],
  "lastModified": "2026-06-17T03:38:00.920",
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