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CVE-2025-6436

Status: ModifiedHigh (8.1)—

Memory safety bugs present in Firefox 139 and Thunderbird 139. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 140 and Thunderbird 140.

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.

Vectores AV:N/PR:N sin UI sugieren explotación remota de aplicación expuesta (T1190). Memory safety bugs en navegador permiten ejecución arbitraria de código (T1059).

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 (2)

Mozilla — FirefoxMozilla — Thunderbird

CWEs

References

Raw JSON (NVD)

Show
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  "id": "CVE-2025-6436",
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