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CVE-2020-27837

Estado: ModificadaMedia (6.4)—

A flaw was found in GDM in versions prior to 3.38.2.1. A race condition in the handling of session shutdown makes it possible to bypass the lock screen for a user that has autologin enabled, accessing their session without authentication. This is similar to CVE-2017-12164, but requires more difficult conditions to exploit.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (1)

Gnome — Gnome Display Manager

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2020-27837",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 4.4,
          "accessVector": "LOCAL",
          "vectorString": "AV:L/AC:M/Au:N/C:P/I:P/A:P",
          "authentication": "NONE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "MEDIUM",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "PARTIAL"
        },
        "acInsufInfo": false,
        "impactScore": 6.4,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 3.4,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 6.4,
          "attackVector": "PHYSICAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "HIGH",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 0.5
      }
    ]
  },
  "affected": [
    {
      "source": "secalert@redhat.com",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "gdm",
          "versions": [
            {
              "status": "affected",
              "version": "prior to 3.38.2.1"
            }
          ]
        }
      ]
    }
  ],
  "published": "2020-12-28T19:15:13.063",
  "references": [
    {
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1906812",
      "tags": [
        "Issue Tracking",
        "Patch",
        "Third Party Advisory"
      ],
      "source": "secalert@redhat.com"
    },
    {
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1906812",
      "tags": [
        "Issue Tracking",
        "Patch",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "secalert@redhat.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-362"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "A flaw was found in GDM in versions prior to 3.38.2.1. A race condition in the handling of session shutdown makes it possible to bypass the lock screen for a user that has autologin enabled, accessing their session without authentication. This is similar to CVE-2017-12164, but requires more difficult conditions to exploit."
    },
    {
      "lang": "es",
      "value": "Se encontró un fallo en GDM en versiones anteriores a 3.38.2.1. Una condición de carrera en el manejo del cierre de sesión hace posible omitir la pantalla de bloqueo para un usuario que tiene habilitado el inicio de sesión automático accediendo a su sesión sin autenticación. Esto es similar a CVE-2017-12164, pero requiere condiciones más difíciles de explotar"
    }
  ],
  "lastModified": "2026-06-17T03:09:42.783",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:gnome:gnome_display_manager:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "4A8BA638-2AED-48BA-BB9D-CD8BEAD2BA9D",
              "versionEndExcluding": "3.38.2.1"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "secalert@redhat.com"
}