Anthropic Rushes to Limit Leak of Claude Code Source Code
Corroborated by 13 sources from 13 publishers
TL;DR
Claude Code's source code appears to have leaked: here's what we know Anthropic has accidentally leaked the source code for its popular coding tool Claude Code. The leak comes just days after Fortune reported that the company had inadvertently made close to 3,000 files publicly available, including a draft blog post that detailed a powerful upcoming model that presents unprecedented cybersecurity risks. The model is known internally as both “Mythos” and “Capybara,” according to the leaked blog post obtained by Fortune.
Sources
1
VentureBeat
https://venturebeat.com/technology/claude-codes-source-code-appears-to-have-leaked-heres-what-we-know
2
Fortune
https://fortune.com/2026/03/31/anthropic-source-code-claude-code-data-leak-second-security-lapse-days-after-accidentally-revealing-mythos
3
Fortune
https://fortune.com/2026/03/31/ai-mirages-alien-machine-brains-anthropic-leaks
4
Ars Technica
https://arstechnica.com/ai/2026/03/entire-claude-code-cli-source-code-leaks-thanks-to-exposed-map-file
5
Ars Technica
https://arstechnica.com/ai/2026/03/entire-claude-code-cli-source-code-leaks-thanks-to-exposed-map-file
6
CNBC 19854910
https://www.cnbc.com/2026/03/31/anthropic-leak-claude-code-internal-source.html
7
The Verge (Tech)
https://www.theverge.com/ai-artificial-intelligence/904776/anthropic-claude-source-code-leak
8
The Verge
https://www.theverge.com/ai-artificial-intelligence/904776/anthropic-claude-source-code-leak
9
TechCrunch
https://techcrunch.com/2026/03/31/anthropic-is-having-a-month
10
CNET
https://www.cnet.com/tech/anthropic-accidentally-exposes-source-code-for-claude-code
11
Bloomberg Technology
https://www.bloomberg.com/news/articles/2026-04-01/anthropic-accidentally-releases-source-code-for-claude-ai-agent
12
Engadget
https://www.engadget.com/ai/claude-code-leak-suggests-anthropic-is-working-on-a-proactive-mode-for-its-coding-tool-150107049.html?src=rss
13
Bloomberg Technology
https://www.bloomberg.com/news/articles/2026-04-01/anthropic-scrambles-to-address-leak-of-claude-code-source-code
14
Dow Jones WSJ
https://www.wsj.com/tech/ai/anthropic-races-to-contain-leak-of-code-behind-claude-ai-agent-4bc5acc7?mod=rss_Technology
15
The Guardian (World)
https://www.theguardian.com/technology/2026/apr/01/anthropic-claudes-code-leaks-ai
16
TechCrunch
https://techcrunch.com/2026/04/01/anthropic-took-down-thousands-of-github-repos-trying-to-yank-its-leaked-source-code-a-move-the-company-says-was-an-accident
17
TechCrunch
https://techcrunch.com/2026/04/01/anthropic-took-down-thousands-of-github-repos-trying-to-yank-its-leaked-source-code-a-move-the-company-says-was-an-accident
18
Seeking Alpha Market News
https://seekingalpha.com/article/4888085-wall-street-lunch-anthropic-tries-to-contain-claude-code-instruction-leak?source=feed_all_articles
19
Ars Technica
https://arstechnica.com/ai/2026/04/anthropic-says-its-leak-focused-dmca-effort-unintentionally-hit-legit-github-forks
20
BleepingComputer
https://www.bleepingcomputer.com/news/security/claude-code-leak-used-to-push-infostealer-malware-on-github