Mozilla Multiple Products Remote Code Execution Vulnerability - Active in CISA KEV catalog.
Description
Mozilla Multiple Products Remote Code Execution Vulnerability - Active in CISA KEV catalog.
AI Analyst Comment
Remediation
FEDERAL DEADLINE: October 26, 2025 (21 days). Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. FEDERAL DEADLINE: October 26, 2025 (21 days). Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA KEV Details
Deadline: October 26, 2025
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.
---METADATA---
VENDOR: Mozilla
PRODUCT: Firefox, Thunderbird, SeaMonkey
AFFECTED_VERSIONS: Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 and 3.0.x before 3.0.10, and SeaMonkey 2.x before 2.0.10
CONFIDENCE: high
MISSING: none
SOURCES_JSON: [{"url":"http://www.securityfocus.com/bid/44425","name":"44425","tags":["vdb-entry","x_refsource_BID"]},{"url":"https://rhn.redhat.com/errata/RHSA-2010-0812.html","name":"RHSA-2010:0812","tags":["vendor-advisory","x_refsource_REDHAT"]},{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=607222#c53","name":null,"tags":["x_refsource_MISC"]},{"url":"http://www.vupen.com/english/advisories/2010/2837","name":"ADV-2010-2837","tags":["vdb-entry","x_refsource_VUPEN"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=646997","name":null,"tags":["x_refsource_CONFIRM"]},{"url":"http://support.avaya.com/css/P8/documents/100114335","name":null,"tags":["x_refsource_CONFIRM"]},{"url":"http://secunia.com/advisories/41965","name":"41965","tags":["third-party-advisory","x_refsource_SECUNIA"]},{"url":"http://secunia.com/advisories/41975","name":"41975","tags":["third-party-advisory","x_refsource_SECUNIA"]}]
PROFILE: grounded@eead9838b633
MODEL: gemini-3.1-flash-lite
GENERATED: 2026-08-29T14:43:10.569Z
---END_METADATA---
Description Summary:
A memory corruption vulnerability in Mozilla products allows unauthenticated remote attackers to execute arbitrary code via crafted JavaScript content.
Executive Summary:
This critical remote code execution vulnerability in multiple Mozilla products is confirmed to be actively exploited in the wild and requires immediate remediation.
Vulnerability Details
CVE-ID: CVE-2010-3765
Affected Software: Mozilla Firefox, Thunderbird, and SeaMonkey
Affected Versions: Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 and 3.0.x before 3.0.10, and SeaMonkey 2.x before 2.0.10
Vulnerability: This is a memory corruption vulnerability triggered when JavaScript is enabled, involving the nsCSSFrameConstructor::ContentAppended function and the appendChild method. It allows an unauthenticated attacker to execute arbitrary code on the host system.
Business Impact
The CVSS score of 9.5 classifies this as a critical vulnerability. Successful exploitation permits full system compromise, enabling attackers to execute malicious payloads, such as the Belmoo malware, which can lead to complete loss of data confidentiality, integrity, and availability. The historical use of this exploit against high profile targets demonstrates its severe potential for reputational damage and organizational disruption.
Remediation Plan
Immediate Action: Update to the patched versions: Firefox 3.5.15, Firefox 3.6.12, Thunderbird 3.0.11, Thunderbird 3.1.7, or SeaMonkey 2.0.11.
Proactive Monitoring: Review system logs for unauthorized binary execution or unexpected network connections associated with known malicious domains or the Belmoo malware family.
Compensating Controls: Disable JavaScript in affected browsers as a temporary measure to prevent the triggering of the vulnerable code path until patches can be deployed.
Exploitation Status
Public Exploit Available: Yes, a Metasploit module and ExploitDB entry exist.
Analyst Notes: This vulnerability is confirmed to be actively exploited in the wild as of October 5, 2025. The flaw was historically used in targeted attacks, such as the compromise of the Nobel Peace Prize website, to distribute the Belmoo backdoor.
Analyst Recommendation
Given the critical severity and confirmed history of active exploitation, immediate patching is mandatory for all affected systems. Organizations must prioritize upgrading to the specified patched versions to eliminate the risk of remote code execution and subsequent malware infection.