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CVE-2026-4701

Status: ModifiedCritical (9.8)—

Use-after-free in the JavaScript Engine component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

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.

Use-after-free en motor JavaScript de Firefox (red sin autenticación, CVSS crítico): explotación remota directa. Permite ejecución arbitraria de código en el navegador.

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

Privileged Account ManagementVulnerability ScanningRestrict Web-Based ContentNetwork SegmentationLimit Software InstallationLimit Access to Resource Over Network

Affected technologies (1)

Mozilla — Firefox

CWEs

References

Raw JSON (NVD)

Show
{
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  "cveTags": [],
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          "options": [
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              "exploitation": "none"
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              "automatable": "yes"
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              "technicalImpact": "total"
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          ],
          "version": "2.0.3",
          "timestamp": "2026-03-26T13:04:34.007549Z"
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  "published": "2026-03-24T13:16:06.103",
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      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2009303",
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        "Permissions Required"
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  "weaknesses": [
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    },
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    }
  ],
  "lastModified": "2026-06-17T10:57:04.077",
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