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CVE-2010-3765

Critical 9.8 Exploited in the wild (KEV)

Confirmed active exploitation — CISA KEV catalog

Name
Mozilla Multiple Products Remote Code Execution Vulnerability
Added to catalog
Remediation due date (US federal)
Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Description

Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 before 3.1.6 and 3.0.x before 3.0.10, and SeaMonkey 2.x before 2.0.10, when JavaScript is enabled, allows remote attackers to execute arbitrary code via vectors related to nsCSSFrameConstructor::ContentAppended, the appendChild method, incorrect index tracking, and the creation of multiple frames, which triggers memory corruption, as exploited in the wild in October 2010 by the Belmoo malware.

Metrics

CVSS 3.1
9.8 (CRITICAL) Score source: CNA CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS — exploit probability
83% (percentile: 100) as of 1 November 2026
CWE
CWE-119

Affected products

mozilla: firefox; mozilla: thunderbird; mozilla: seamonkey

References