Mozilla Multiple Products Remote Code Execution (CVE-2010-3765)

Historical catalog analysis: CISA added this entry on October 06, 2025. The entry reflects catalog information retrieved on August 31, 2026, not a snapshot archived on the inclusion date. Check current vendor guidance before acting.

What the vulnerability is

CVE-2010-3765 is a remote code execution (RCE) vulnerability affecting multiple Mozilla products. The flaw stems from memory corruption triggered when JavaScript is enabled. Specifically, the vulnerability involves vectors related to the appendChild method and nsCSSFrameConstructor::ContentAppended, where incorrect index tracking during the creation of multiple frames allows an attacker to execute arbitrary code.

Exposure and applicability

This vulnerability applies to environments running affected versions of Mozilla Firefox, SeaMonkey, and Thunderbird. The primary exposure path is the processing of malicious content via a web browser or email client with JavaScript enabled. Because this flaw involves memory corruption at the application level, any system hosting these specific software products in a configuration that allows JavaScript execution is potentially susceptible.

Remediation priorities

Based on the inclusion of this vulnerability in the CISA Known Exploited Vulnerabilities catalog, remediation should be prioritized for assets exposed to untrusted external content. Our analysis suggests the following priority sequence:

1. Immediate Patching: Apply vendor-supplied mitigations and updates for Firefox, SeaMonkey, and Thunderbird. This is the primary method to resolve the underlying memory corruption flaw.
2. Asset Decommissioning: For legacy systems where patches are unavailable or cannot be applied without breaking critical functionality, these products should be discontinued in favor of supported alternatives.
3. Cloud Service Alignment: Organizations utilizing cloud-delivered browser services should ensure their providers have aligned with BOD 22-01 guidance regarding the remediation of known exploited vulnerabilities.

How to validate remediation

Verification must move beyond simple version checks, as a version number does not inherently prove that a specific security patch was successfully applied and active in memory. To verify exposure reduction, defenders should:

• Confirm Patch Application: Cross-reference the installed build version against the specific vendor advisory (MFSA2010-73) to ensure the fix for nsCSSFrameConstructor::ContentAppended is present.
• Configuration Audit: Verify that JavaScript settings are managed according to organizational risk tolerance, though disabling JavaScript is a compensating control rather than a primary fix for the vulnerability itself.

Limits and open questions

While the technical trigger (memory corruption via frame creation) is identified, the source does not specify which exact versions of each product are affected. Furthermore, while CISA has added this to the known exploited catalog, it remains unknown if this specific CVE is currently being utilized by ransomware campaigns. Residual risk remains for organizations using customized or modified builds of Mozilla products where standard vendor patches may not apply directly.

Source and editorial note

CVE-2010-3765: Mozilla Multiple Products Remote Code Execution Vulnerability · Source date: October 06, 2025 · Retrieved August 31, 2026.

Material facts are tied to the cited primary source. Recommendations are independent defensive analysis unless attributed to the source. Confirm consequential decisions against current authoritative guidance.

Archive date: October 09, 2025. The displayed post date is assigned three days after the source date to organize this retrospective archive; it does not mean this site published the analysis then. First published by this site: October 01, 2026 at 00:10 UTC.

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