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CVE-2026-2803

Status: ModifiedHigh (7.5)—

Information disclosure, mitigation bypass in the Settings UI component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.

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).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

Vector CVSS AV:N/AC:L/PR:N/UI:N indica explotación remota sin privilegios ni interacción (T1190). CWE-200 y descripción de 'information disclosure' confirman lectura de datos sensibles (T1005) en componente Settings UI de Firefox/Thunderbird.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Vulnerability ScanningPrivileged Account ManagementNetwork SegmentationLimit Access to Resource Over NetworkFilter Network TrafficApplication Isolation and Sandboxing

Affected technologies (2)

Mozilla — FirefoxMozilla — Thunderbird

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2026-2803",
  "cveTags": [],
  "metrics": {
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      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-2803",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-02-26T20:00:43.091717Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Primary",
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        "cvssData": {
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          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
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        "impactScore": 3.6,
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      },
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  "published": "2026-02-24T14:16:28.810",
  "references": [
    {
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2012012",
      "tags": [
        "Permissions Required"
      ],
      "source": "security@mozilla.org"
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-13/",
      "tags": [
        "Vendor Advisory"
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    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-16/",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "security@mozilla.org"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
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          "lang": "en",
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        },
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  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Information disclosure, mitigation bypass in the Settings UI component. This vulnerability was fixed in Firefox 148 and Thunderbird 148."
    },
    {
      "lang": "es",
      "value": "Revelación de información, elusión de mitigación en el componente de la interfaz de usuario de Configuración. Esta vulnerabilidad afecta a Firefox < 148 y Thunderbird < 148."
    }
  ],
  "lastModified": "2026-06-17T10:31:48.210",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
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}