‹ Back to list

CVE-2021-21402

Status: ModifiedMedium (6.5)—Exploit
Severity6.5Medium · CVSS 3.1
Exploitation probability79 %higher than 100% of CVEs
Active exploitationNonot in the CISA catalog
Public exploitAvailableProof of concept on GitHub (unverified) · Nuclei template (automated mass detection)

Jellyfin is a Free Software Media System. In Jellyfin before version 10.7.1, with certain endpoints, well crafted requests will allow arbitrary file read from a Jellyfin server's file system. This issue is more prevalent when Windows is used as the host OS. Servers that are exposed to the public Internet are potentially at risk. This is fixed in version 10.7.1. As a workaround, users may be able to restrict some access by enforcing strict security permissions on their filesystem, however, it is recommended to update as soon as possible.

CVSS

Base score
6.5
Version
3.1
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days
79 %
Percentile among all scored CVEs
100
Score date
10/27/2026

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).

Public exploits

Exploit code or detection templates are publicly available. This is not the same as confirmed active exploitation (KEV), but it raises the risk: patch with priority.

⚠️ GitHub proofs of concept are not verified: some are fake or contain malware. Never run them outside an isolated lab.

Affected technologies (1)

Jellyfin — Jellyfin

CWEs

References

Show 6 references

Raw JSON (NVD)

Show
{
  "id": "CVE-2021-21402",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 4,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:S/C:P/I:N/A:N",
          "authentication": "SINGLE",
          "integrityImpact": "NONE",
          "accessComplexity": "LOW",
          "availabilityImpact": "NONE",
          "confidentialityImpact": "PARTIAL"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 8,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security-advisories@github.com",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 7.7,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 4,
        "exploitabilityScore": 3.1
      },
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 6.5,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 2.8
      }
    ]
  },
  "affected": [
    {
      "source": "security-advisories@github.com",
      "affectedData": [
        {
          "vendor": "jellyfin",
          "product": "jellyfin",
          "versions": [
            {
              "status": "affected",
              "version": "< 10.7.1"
            }
          ]
        }
      ]
    }
  ],
  "published": "2021-03-23T20:15:13.120",
  "references": [
    {
      "url": "https://github.com/jellyfin/jellyfin/commit/0183ef8e89195f420c48d2600bc0b72f6d3a7fd7",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/jellyfin/jellyfin/releases/tag/v10.7.1",
      "tags": [
        "Release Notes",
        "Third Party Advisory"
      ],
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/jellyfin/jellyfin/security/advisories/GHSA-wg4c-c9g9-rxhx",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/jellyfin/jellyfin/commit/0183ef8e89195f420c48d2600bc0b72f6d3a7fd7",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://github.com/jellyfin/jellyfin/releases/tag/v10.7.1",
      "tags": [
        "Release Notes",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://github.com/jellyfin/jellyfin/security/advisories/GHSA-wg4c-c9g9-rxhx",
      "tags": [
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-22"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Jellyfin is a Free Software Media System. In Jellyfin before version 10.7.1, with certain endpoints, well crafted requests will allow arbitrary file read from a Jellyfin server's file system. This issue is more prevalent when Windows is used as the host OS. Servers that are exposed to the public Internet are potentially at risk. This is fixed in version 10.7.1. As a workaround, users may be able to restrict some access by enforcing strict security permissions on their filesystem, however, it is recommended to update as soon as possible."
    },
    {
      "lang": "es",
      "value": "Jellyfin es un sistema multimedia de software libre.&#xa0;En Jellyfin versiones anteriores a 10.7.1, con determinados endpoints, las peticiones bien diseñadas permitirán la lectura de archivos arbitrarios desde el sistema de archivos de un servidor Jellyfin.&#xa0;Este problema es más frecuente cuando es usado Windows como el Sistema Operativo host.&#xa0;Unos servidores que están expuestos a la Internet pública están potencialmente en riesgo.&#xa0;Esto es corregido en versión 10.7.1.&#xa0;Como solución alternativa, los usuarios pueden ser capaces de restringir algunos accesos imponiendo permisos de seguridad estrictos en su sistema de archivos; sin embargo, se recomienda actualizar lo antes posible"
    }
  ],
  "lastModified": "2026-06-17T03:35:29.773",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:jellyfin:jellyfin:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "F1DD62BC-C2DF-4847-8580-CEA58D17D528",
              "versionEndExcluding": "10.7.1"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "security-advisories@github.com"
}