Is itCheck something

No. CVE-2010-3765

A Mozilla (several products) bug is being used in attacks

Being used now

Yes. Attackers are using this right now.

What to do

Apply the vendor's update. If there is none, stop using it or cut it off from the internet.

Confirmed in attacks
Oct 6, 2025
Product
Mozilla (several products)
Attack likelihood, next 30 days
83%

Attack likelihood is EPSS, a daily estimate from FIRST.org of how likely this bug is to be used in attacks in the next 30 days.

The official description

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.

For your tech helper

A read-only checklist for whoever helps you with your computer, or an AI assistant. Paste it into Claude, ChatGPT or a coding agent; it only looks and changes nothing.

Read-only check, change nothing, send nothing anywhere.
Is Mozilla Multiple Products (CVE-2010-3765) installed or running on this machine or in this project?
1. Find every copy and its version (apps, packages, containers, lockfiles).
2. Compare each version against the vendor's fixed version for CVE-2010-3765. Quote the vendor page you used.
3. Report a table: where, version, fixed version, status (exposed / fixed / not installed / unsure).
4. List the exact update steps, but do not run them.

Sources