CVE entry · CVE-2010-3765
CVE-2010-3765: Mozilla Multiple Products Remote Code Execution Vulnerability
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.
- Actively exploited: added to CISA’s KEV catalog on October 6, 2025.
- Use by ransomware: not established so far.
- Remediation deadline for US federal agencies: October 27, 2025.
Description from CISA’s KEV catalog.
What to do
- Check whether your estate includes affected Mozilla products, including internet-facing devices.
- Apply the vendor’s patch or mitigations (references below). Failing that, isolate the product or stop using it, as CISA requires of US federal agencies.
- An exploited vulnerability has often been used before it was fixed: look for signs of compromise, especially on internet-facing devices.