---
title: "Claude found 22 security flaws in Firefox in two weeks"
description: "In a partnership with Mozilla, Claude Opus 4.6 found Firefox vulnerabilities, 14 of them high-severity."
url: https://kurddevelopers.com/en/news/claude-finds-22-firefox-vulnerabilities
language: en # English
type: news
published: 2026-03-06T19:00:00.000Z
updated: 2026-11-02T00:23:47.000Z
author: "Osamah Ismail"
author_url: https://kurddevelopers.com/en/author/1
section: "Security"
tags: ["Anthropic","Claude","Firefox","Mozilla","security"]
sources: ["Anthropic","Mozilla","TechCrunch"]
image: https://kurddevelopers.com/uploads/2026/11/claude-chrome-ext-email-hero-hero-c6257fa5.webp
translations:
  ku: https://kurddevelopers.com/news/claude-finds-22-firefox-vulnerabilities
  ar: https://kurddevelopers.com/ar/news/claude-finds-22-firefox-vulnerabilities
publisher: Kurd Developers
publisher_url: https://kurddevelopers.com/
---

# Claude found 22 security flaws in Firefox in two weeks

> In a partnership with Mozilla, Claude Opus 4.6 found Firefox vulnerabilities, 14 of them high-severity.

![Image: Anthropic](https://kurddevelopers.com/uploads/2026/11/claude-chrome-ext-email-hero-hero-c6257fa5.webp)

## What was found?

In a security partnership with Mozilla, Anthropic's team used Claude Opus 4.6 to find 22 vulnerabilities in the Firefox browser over two weeks.

- 14 were rated high-severity.
- The work started with the JavaScript engine.

## Were they fixed?

Yes. Most were fixed in Firefox 148, released in February. A few fixes are coming in the next release.

## Can Claude hack?

Anthropic spent $4,000 in API credits having Claude build proof-of-concept exploits for the bugs. Claude succeeded in only two cases.

In other words, AI is very good at finding vulnerabilities but still weak at turning them into working attacks.

## For you

If you use Firefox, make sure you are on the latest version.

**Sources:** Anthropic, Mozilla, TechCrunch

---

Published by [Kurd Developers](https://kurddevelopers.com/) on 2026-03-06. Cite as: “Claude found 22 security flaws in Firefox in two weeks”, Kurd Developers, https://kurddevelopers.com/en/news/claude-finds-22-firefox-vulnerabilities