---
id: "CVE-2010-3765"
kind: "vulnerability"
aliases: ["CVE-2010-3765"]
title: "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\u2026"
severity: "critical"
cvss: 9.8
epss: null
exploited: true
status: "open"
category: "other"
products: [{"name": "Mozilla Multiple Products", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.5", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.5.1", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.5.2", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.5.3", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.5.4", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.5.5", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.5.6", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.5.7", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.5.8", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.5.9", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.5.10", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.5.11", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.5.12", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.5.13", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.5.14", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.6", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.6.2", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.6.3", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.6.4", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.6.6", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.6.7", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.6.8", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.6.9", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.6.10", "ecosystem": "vendor"}, {"name": "mozilla firefox", "fixed": [], "affected": "= 3.6.11", "ecosystem": "vendor"}, {"name": "mozilla thunderbird", "fixed": [], "affected": "= 3.0.1", "ecosystem": "vendor"}, {"name": "mozilla thunderbird", "fixed": [], "affected": "= 3.0.2", "ecosystem": "vendor"}, {"name": "mozilla thunderbird", "fixed": [], "affected": "= 3.0.3", "ecosystem": "vendor"}, {"name": "mozilla thunderbird", "fixed": [], "affected": "= 3.0.4", "ecosystem": "vendor"}, {"name": "mozilla thunderbird", "fixed": [], "affected": "= 3.0.5", "ecosystem": "vendor"}, {"name": "mozilla thunderbird", "fixed": [], "affected": "= 3.0.6", "ecosystem": "vendor"}, {"name": "mozilla thunderbird", "fixed": [], "affected": "= 3.0.7", "ecosystem": "vendor"}, {"name": "mozilla thunderbird", "fixed": [], "affected": "= 3.0.8", "ecosystem": "vendor"}, {"name": "mozilla thunderbird", "fixed": [], "affected": "= 3.0.9", "ecosystem": "vendor"}, {"name": "mozilla thunderbird", "fixed": [], "affected": "= 3.1.1", "ecosystem": "vendor"}, {"name": "mozilla thunderbird", "fixed": [], "affected": "= 3.1.2", "ecosystem": "vendor"}, {"name": "mozilla thunderbird", "fixed": [], "affected": "= 3.1.3", "ecosystem": "vendor"}, {"name": "mozilla thunderbird", "fixed": [], "affected": "= 3.1.4", "ecosystem": "vendor"}, {"name": "mozilla thunderbird", "fixed": [], "affected": "= 3.1.5", "ecosystem": "vendor"}, {"name": "mozilla seamonkey", "fixed": [], "affected": "= 2.0", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["desktop", "exploited", "firefox", "other", "seamonkey", "thunderbird"]
not_affected_if: ["javascript-disabled", "modern-release-installed"]
published_at: "2010-10-28T00:00:05+00:00"
first_seen_at: "2026-10-23T19:11:51+00:00"
updated_at: "2026-10-23T23:44:51+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2010-3765", "first_seen_at": "2026-10-23T19:11:51+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2010-3765", "first_seen_at": "2026-10-23T23:44:51+00:00"}]
---

# 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…

Mozilla Firefox, SeaMonkey and Thunderbird have a memory corruption bug in the layout code (nsCSSFrameConstructor::ContentAppended) that is triggered by JavaScript that appends DOM nodes. A remote attacker who gets a user to load a crafted page can run arbitrary code as that user.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Mozilla Multiple Products affected ? fixed ?
- vendor:mozilla firefox affected = 3.5 fixed ?
- vendor:mozilla firefox affected = 3.5.1 fixed ?
- vendor:mozilla firefox affected = 3.5.2 fixed ?
- vendor:mozilla firefox affected = 3.5.3 fixed ?
- vendor:mozilla firefox affected = 3.5.4 fixed ?
- vendor:mozilla firefox affected = 3.5.5 fixed ?
- vendor:mozilla firefox affected = 3.5.6 fixed ?
- vendor:mozilla firefox affected = 3.5.7 fixed ?
- vendor:mozilla firefox affected = 3.5.8 fixed ?
- vendor:mozilla firefox affected = 3.5.9 fixed ?
- vendor:mozilla firefox affected = 3.5.10 fixed ?
- vendor:mozilla firefox affected = 3.5.11 fixed ?
- vendor:mozilla firefox affected = 3.5.12 fixed ?
- vendor:mozilla firefox affected = 3.5.13 fixed ?
- vendor:mozilla firefox affected = 3.5.14 fixed ?
- vendor:mozilla firefox affected = 3.6 fixed ?
- vendor:mozilla firefox affected = 3.6.2 fixed ?
- vendor:mozilla firefox affected = 3.6.3 fixed ?
- vendor:mozilla firefox affected = 3.6.4 fixed ?
- vendor:mozilla firefox affected = 3.6.6 fixed ?
- vendor:mozilla firefox affected = 3.6.7 fixed ?
- vendor:mozilla firefox affected = 3.6.8 fixed ?
- vendor:mozilla firefox affected = 3.6.9 fixed ?
- vendor:mozilla firefox affected = 3.6.10 fixed ?
- vendor:mozilla firefox affected = 3.6.11 fixed ?
- vendor:mozilla thunderbird affected = 3.0.1 fixed ?
- vendor:mozilla thunderbird affected = 3.0.2 fixed ?
- vendor:mozilla thunderbird affected = 3.0.3 fixed ?
- vendor:mozilla thunderbird affected = 3.0.4 fixed ?
- vendor:mozilla thunderbird affected = 3.0.5 fixed ?
- vendor:mozilla thunderbird affected = 3.0.6 fixed ?
- vendor:mozilla thunderbird affected = 3.0.7 fixed ?
- vendor:mozilla thunderbird affected = 3.0.8 fixed ?
- vendor:mozilla thunderbird affected = 3.0.9 fixed ?
- vendor:mozilla thunderbird affected = 3.1.1 fixed ?
- vendor:mozilla thunderbird affected = 3.1.2 fixed ?
- vendor:mozilla thunderbird affected = 3.1.3 fixed ?
- vendor:mozilla thunderbird affected = 3.1.4 fixed ?
- vendor:mozilla thunderbird affected = 3.1.5 fixed ?
- vendor:mozilla seamonkey affected = 2.0 fixed ?

## How to check

Check the installed Firefox, SeaMonkey or Thunderbird version against the vendor's fixed release.

## Fix

Upgrade Firefox, SeaMonkey and Thunderbird to a currently supported release.
If upgrading is not possible, disable JavaScript in the affected browser or discontinue use of the product, per CISA guidance.

## Timeline

- 2026-10-23T19:11:51+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2010-3765
- 2026-10-23T23:44:51+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2010-3765

## From the sources

Mozilla Firefox, SeaMonkey, and Thunderbird contain an unspecified vulnerability when JavaScript is enabled. This 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.

CISA 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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_